As far as Kubricks go, I'd have to defer opinion on that to the guys who collect(ed) them... Intentional "chase" figures like that in a case tend to make me feel a little differently (IE: You buy the case, and the cost spreads out differently over the chase figure cmopared to the regular figures), but that's just my opinion and I don't buy Kubes to really know how to feel. I bought similar figures like Hot Toys' Snap Kit figures, and their chases are pretty rare, and I got the rarest. I'd probably not feel compelled to sell that one for the same price as others in the case. They're also out of production though too, haha.
Unless you live in Japan, Kubricks have no "retail price". Their value is totally subjective, especially for the chase figures. So to me the only rule of thumb would be to sell them on JD at or below their going rate on ebay, which from what I've seen is almost always the case. The times I've seen people asking too much for kubs on JD, I've simply rolled my eyes and moved on or politely asked if they could work something out with me. Seems like everyone is adult enough that no regulation is necessary. Hell, I'd rather somebody listed kubs marked slightly too high than not list them at all, just cuz it's fun to see what's for sale. But that's just me.
I would think that would /should be the case for other toy lines too, but I kind of agree with the 1 year rule if it deters actual scalpers
who actively scour toy stores just to flip toys and make a profit here. They can always take their goods to ebay. But I think it's a bit hostile to call a collector who happens to have a spare HTF figure a scalper if he's asking fair market value or less.