I do a lot, although there are a few things to clarify here:
If I'm going to pay so-called "ebay prices" as people tend to call it (really just the average the game is selling for at the time) then I will look around to see if I can find it cheaper elsewhere first. I'll check online websites and local places before doing so.
If I'm paying this price then it's because I actually want the game and to play it. It's not often that I'll just pick it up when it costs more than what it's worth if I'm not sure I'll even like it.
If I'm paying this price for a "rare" game then it's because I'm just not going to find it at a decent price. I'm sorry, but it simply just isn't easy to go and find a CIB Albert Odyssey for Saturn under $80. In fact at this point, $80 would almost be considered a deal. It happens, yes. It isn't as common as some people make it out to be though.
I really don't see what the big deal about this is, honestly. Most used games stores and places like that, at least around here anyway, have nothing more than sports games and a few dozen copies of really common games like Super Mario Bros. / Duck Hunt and F-Zero. It's difficult, for me at least, to find the good stuff just out in the wild. It's gotten to the point - I think for game collectors in general now - that even going to garage sales is pretty competitive because there are so many resellers now just everywhere. Yes, I agree that, for example, $20 for a loose cart of Castlevania III costs too much. Yes, I agree that resellers are screwing collectors over. But I'm not going to sit around and wait for months in the hopes that I can find it for $5 or less. I'm going to buy it if I want it. And I'm okay with that. There are a lot more people that do that than will admit, for some reason. I'm pretty sure it's the same as people who were shown in a study to own a Mac but were afraid to openly admit that they had computer issues with it because "Macs aren't supposed to have computer issues" and because they paid so much more for it than they would a PC. For some reason, people think that paying more for something than someone else may have paid for it is somehow embarrassing. Yeah, I'd love to go out and pick up Earthbound for $10 like I know some people have (or at least claimed to). That sort of thing just doesn't happen that often and it doesn't happen to everyone.
I'm not accusing any of you of lying about how much you've paid for anything, by the way. I know a lot of collectors do, but unless I knew for sure I would never explicitly accuse anyone of that. Because why lie about it? It's silly.
In my sig below you'll see I bought Mario Party recently. I paid $30 for it. That's way more than what it should actually be sold for, but after searching for a month, that was the best price I could find. I'm not ashamed of it because I'll play it with my friends and have a good time. The game is not less fun just because I didn't find it at Goodwill for $1.