Big cities aren't the gold mine you probably dream they are. The amount of re-sellers and flippers has increased ten fold in the past year or two. My local facebook groups are full of stay at home moms posting "ISO: Super Nintando and Mario games!" and bundles of crappy games at 95% FMV because they're HOOKIN' UP THE COLLECTORS WITH LOWER THAN EBAY PRICES!!
Craigslist still has deals but instead of getting them, you play a fun game called, "see what you missed" if you are later than 4 minutes in responding. Even then, the resellers will offer higher than the asking price. I have had many deals fall through because flippers have e-mailed after offering more. I see those same deals posted in the Facebook groups the next day, using the same pictures but for $20 higher than the flipper paid for it.
Yard sales have become a shit show as well. I watched two flippers last year almost get into a fist fight over a $40 PSP that they were going to flip because apparently they both saw eachother at an earlier garage sale, and one guy bought something out of the other guys hand (offered the seller more money which they took). Complete with swearing, flipping off, and peeling tires. Then some fat girl came when I was looking at the leftovers and pushed me out of the way and started rifling through the games, then left quickly to go to the next garage sale.
The local Goodwills have a score or two once a year, but most of the time I see crackhead looking folks picking up every copy of every game, typing stuff into their phone, and then abandoning the games at whatever secluded part of the store they chose to look up their crap in. Although in the past 6 months or so most of the stuff is going to the online auction sites. Goodwills here sell on Amazon, Ebay, and have their own site. The value villages have their own Ebay sites.
All in all, I just don't really care anymore. I've got all the games I want for my collection and the one or two I do occasionally want or look interesting I will just pick up on Ebay. At least with Ebay I don't have to leave my house and interact with people.
It's become a complete and total shitshow of people willing to get in actual fights over old copies of Mario so they can make $20. Just not worth the effort anymore.