I saw a set of six on FB Marketplace for $250.  Seems going rate for single figures are about $40 on there.

Probably over a decade ago it was a daily stop for me.  The photo archive is still a good resource, especially for determining when something was released and what it originally sold for.  That is really the only thing I have used the site for recently.

I have sold a bunch of Star Wars stuff through marketplace.  There is nothing that restricts getting paid before shipping.  Perhaps they do if you pay through facebook itself.  Honestly FB only gets involved if you are trying to list something illegal.  The bots will generally block a listing for a replica blaster, they have even blocked lightsaber hilt replicas calling it a weapon.

As for listings, I always offer shipping.  I generally list items as $XXX or best offer plus shipping.  All my payments have either been cash in person or paypal for items I have shipped.  I have always been paid first before shipping an item.  Overall, it is so much easier than ebay and you are only paying fees for paypal payments.

You do find you get a lot of people who want something for nothing or people that just don't respond.  Essentially any listing you click on has a standard "is this item still available" message button.  You get a lot of those messages from people who then don't respond when you tell them it is available.  You also get a lot of "I'll pay you $50 shipped for the item you have listed for $100 that will cost $25 to ship".  They are quite persistent in stating they have the money ready to go and that even though the item has sold on ebay $100, ebay and paypal takes fees, so their $50 offer is really generous.  Also they act like they are doing you a favor by having you ship the item rather than meeting to pick it up.  Also be wary of overseas buyers.  I have made a lot of great deals overseas, but also a lot of headaches dealing with them.  No offense to Australians, but a lot of them are a huge pain in the rear.  I have had countless inquiries about multiple lots of stuff.  Put everything together to get a shipping quote, then deleted stuff to get a lower quote, to then finally say, "oh, what about import tax, I can't offer as much because I have to pay that".  As a general rule of thumb, anything over around six pounds is $100 to ship to Australia.  Additionally, USPS only insures up to $200 to Australia.  UPS and Fedex do not want to ship internationally.  Every quote from them is $500.

So overall, it is quite doable, especially if you get local buyers.  At this point, in past year to year and a half, I have sold the following:

All my carded figures from orange carded POTF2 through the beginning of the black series (1995 to 2008 or so)
All my battlepacks, deluxe figures, exclusive figures, etc. (essentially everything that isn't a standard carded figure, but not a vehicle)
All my loose figures (bulk detail to a guy in the UK - he even used a parcel broker, so DHL came to my house to pick everything up, I just had to box it, print out the labels he sent, and fill out a customs form)
A majority of my loose vehicles and beasts (still have several lots listed)
A majority of boxed vehicles and beasts (again, all remaining items are listed, I'm down to 42 items left grouped into several lots)
30 Sideshow 12" figures and counting (starting with prequel items, 19 figures left plus 60 OT items, which I will probably keep a decent amount of)
Several Master Replicas items

Once I get all my listed items sold, I'm moving on to attempting to unload my Hasbro 12" series, then I'm sorting through Legos to see what I want to keep.

Just know that this does take a lot of time and effort between sorting through stuff, taking pictures, and making listings.  My dining room has been a staging area for the past year or so.  Stuff comes up from the basement, then I take pictures and make listings, and just leave it in the dining room until it sells.  You will probably get inquiries from dealers who will offer to buy everything, but that will really lowball you.  At this point, I have made a really decent profit overall, especially since I have sold stuff that I never thought I could unload and the vast majority at cost or above.

So easy answer, definitely go with FB marketplace.  It is really nice when you make a sale and just have to drive a few miles down the road for an in person pick up.  Otherwise, definitely get a digital scale.  I got one on amazon for $25.  It has a 110 lb capacity and I have weighed boxes that are 24" on a side on it.  Also remember that USPS are supposed to measure a box that has any dimension greater than 12".  They always remember on very large boxes, but not always on the smaller ones that they should be measuring.  That will up the shipping price.  Also, they have a max size.  The 24" a side boxes are too large to ship via USPS and have to go UPS.

DC's problem at this point is that they have already semi-rebooted with no true plans in sight.  JJ Abrams is doing a new Superman movie without Cavell.  Pattinson is Batman.  The Flash movie is supposedly still happening, but Cyborg has been booted.  Aquaman 2 is supposedly still happening.  They are making Black Adam and Shazam 2, which really is a waste.  Imagine Marvel saying, well we had some problem with Age of Ultron, so we're scrapping Infinity War, but her is Iternals and Shang-Chi, enjoy.

At this point, they are too far behind to completely reboot and start over, even if they tried to make Wandavision style shows.  Who wants to see yet another Superman or Batman origin story?  I think the MCU shows work in part because they started as movie characters.  So far they are smaller characters who never would have gotten this type of back story or focus in an ensemble piece.

Honestly, if DC were smart, I would movie towards a Justice League 2 based on Batman's end of the world dreams.  That seems far more interesting than anything they have on their slate.  The fact you have all these superheros and you have already changed actors on the two biggest doesn't bode well.  They released their team move four years ago and now have no plans for another is not a positive thing.  It isn't an easy world for movies in general right now.  Who knows how much longer the superhero boom can last in these conditions.

I'm in the same boat.  It has just gotten to be too much.  At this point, I've just started to sort through everything.  I am thinking of keeping more of the bigger playsets, like the Death Star, Cloud City, Ewok Village, etc.  I haven't got to the point of selling yet.  I would probably start with unopened sets.  At this point, I have been concentrating on selling off Hasbro stuff.  After about a year or so, I finally see light at the end of the tunnel.  I have sold off all of my 3 3/4" carded and loose figures and all my multipacks and deluxe figures.  I'm down to around 50 items left that are mostly vehicles at this point.  Then is task of trying to unload Hasbro 12", which I am doubting has much resale value.

I have had a couple of bulk sales.  I sold all my loose figures to one person.  I'm sure I could have gotten more money if pulled out certain figures and sold them separate, but it was so much easier not to have to sort and take pictures.

For Legos, I am sure a bulk sale is easily possible.  However, they are worth a lot and I'm sure a bulk buyer won't even pay MSRP on sets bought in bulk.  Everything I have sold with very few exceptions have been on FB marketplace.  That has been a relatively easy process.  Honestly, if you have the time, especially on sealed sets, I would try selling them individually or in small lots.  You will get the best return that way.

I have been tracking my collection in excel sheet for quite some time.  When I started selling, my desire was to try to cover what I paid for everything.  I figured that would be a tough order, but I have actually been successful so far.  Really, my Hasbro 12" figures are the only thing left I think I will take a loss on.  All it takes is time and patience.

I am getting tempted on this one.  I have been selling off my collection and haven't been buying much Hasbro for several years.  I don't have a single Mando figure, so I figured it was an easy pass.  I still haven't found room to open and display the Barge yet, so buying another large vehicle didn't seem practical.  However, the one thing I have been buying has been the retro figures, mainly to keep carded.  I have been buying two of the figures like Tarkin that were never made in the original line.  So what does Hasbro do?  They make a line of retro Mandalorian figures which I have preordered two of each, including the Stormtrooper that comes with the Monopoly game.  So now I could display this with the retro figures and not have to worry about hunting down a bunch of Mando figures I never purchased.  I guess I have a little over a week to decide.

After a few experiences shipping stuff overseas, I am really beginning to believe all the shipping services in the US are a giant scam.  I have been selling off a lot of my Hasbro stuff and most of the buyers are located overseas.  For several packages, I used USPS to ship.  In one week, I shipped to the UK, Germany, and Australia from the east coast US.  UK took two weeks, Germany three, and Australia close to two months, with around a month of it being stuck in US customs.  My last few shipments have been bulk buys shipped to the UK.  The buyer arranged the shipments through a parcel broker.  Each shipment has been 5 to 7 large boxes.  DHL has come to my house, picked up the boxes, and had them delivered in 36 to 48 hours after pick up.  My last shipment was picked up at 5:00 PM EST on Monday and was delivered Wednesday at 9:30 AM.  No clue how much it costs, but it really shows that shipping doesn't have to be the disaster we have been seeing.