Welcome to the forum and sorry to hear that you were forced to sell.
Right now i am selling my rare G1 sized steelbooks.
I stopped colleting G1 sized a while back ago, these rare ones were just the ones i was holding off as a sentimental value due nor only to their rarity but also because of being franchises i really like (Dishoned and Assassins Creed) and the reason i decided to sell them now is because I'm going on a vacations trip to Mozambique in October and between tickets, visa, etc is a lot of money, so its nice to make some extra money to help me pay for it.
Others sell to pay for other stuff, some others just because they reached a point where they are done with collecting, some times people sell stuff just so they can free up space to buy more stuff lol
Regarding prices, if there is a big difference in values for the same product, normally the real price is in between the highest and the lowest asking price.