It seems like you are seeking highest price possible for anything you sell. best bet in that case is sticking to ebay and using a very high start bid, see if you get lucky or setting a reserve on anything you list so if it doesn't meet your expectations you get to keep it.
Forum prices and ebay prices can have some stark contrasts, mostly we're collectors on the forums and know how easy, or difficult various ponies or acc are to acquire. So, usually there's a more narrow selling range happening on the pony forums, if collectors feel a price is too high they'll pass that sale and a $40+ dollar minty for sale here would sit around, FAR longer then on ebay. I would hazard to say a $40 FF minty wouldn't sell here at all unless she had her backcard and accessories, but as you see it is not the same on ebay.
On ebay you not only have collectors shopping but many,
many more people who are
not collectors, do not know average pricing and will bid what they want for items. When I sold there, I would regularly be shocked at the ending prices of some of my auctions that I started at 99cents! "beddy bye eye" ponies ending for $20 each alone, pony bride for $30, Sundance for $25 all of those are a struggle to get $6 each here on the forums, I sold my last pony bride here for $3.
99% of the time too, on the auctions that surprised me with those crazy high ending prices my buyers were
not collectors, but people who knew little about MLP and were bidding to get a gift, or wanted one for nostalgia. It's an entirely different market. Perfect example, when I first met and started dating my fiancee we went to a toyshow together and he was SO excited as he found me a diamond keyper for $10 and gifted her to me there. When we got home he showed me the same one on his ebay watchlist he was going to buy for me as a surprise... it was a BIN for $135.00 + shipping. That toy is "worth" about $20 but he had no idea as he didn't see all the completed listings, didn't look them up, He just saw something he felt was a "perfect gift" regardless of price would have paid it.
there are a lot of those buyers on ebay! You won't find them on collectors forums though.