The cost of shipping one of those mothers would likely minimize the value a bit; they're big and heavy. But just FYI, there are different versions, one with silver legs, which is the more common release, and then a classic comic color variant that has purple legs. If you find one with purple legs, that can be good trade bait.
Another thing to look for is Galactus. Again, there are two versions, one that's lighter colored with blue and purple, and one that's...um, dark blue and dark purple. The Dark Galactus is the variant. I found two of them at TJ Maxx a couple months ago (kept one for me and gave the other to my friend who runs this Galactus fan site
. Either Galactus is kind of hard to find, but most people who collect this line have one, but if they don't, they'll want him really bad.