I miss the days of hunting for my games on the cheap in the wild, but the hunt is essentially head now. All the thrift stores I used to score at regularly have either gone out of business or have become incredibly greedy, often charging more than what the local game stores charge for the same games. We have one flea market in my state and it used to be a goldmine, but now is all resellers trying to flip the same sun damaged games for way too much money. All the pawn shops have wised up to games being highly desirable and price most of their games accordingly now. This really only leaves a few used media shops and garage sales to find the occasional good deal. However, the amount of effort to do so, as well as all the aforementioned places far outweighs the potential payoff 99.9% of the time now. Oh, and there are also indie game stores, but virtually all the ones left are overpriced or at least are on the high end of ebay.
This has resulted in me using ebay 90% of the time to purchase retro games at least. For newer releases I just go to Gamestop now. Luckily before things got really bad I was able to acquire 95% of all the games I'd ever wanted so the chances of me finding one of these last few games on my want list are very slim now. Also, it's just way easier, convenient, and frankly cheaper just to buy a specific game on ebay and be done with it. I still try to get deals on ebay by keeping an eye out for auctions or low BINs, but either way this is how I buy my retro games now. I do hope that someday retro gaming will die down enough where there will be a decent chance that going out will yield some good finds, but even if it did it wouldn't be even close to how good it used to be.