Mind just came back to me from reading other peoples' stuff.
Wild Arms - I got this at a Music for a Song (I think) in Gatlinburg when I was like 12. Knew nothing about it, was getting into RPGs though and it LOOKED interesting. And I was on vacation and this was before smart phones, so I couldn't look anything up on it.
It's not like one of my all time favorites, but it's still a game I really enjoy for a lot of reasons.
Final Fantasy Legend 2 - Got it at a Target on the way home from Florida when I was like, 10 or 11. Probably the Target in Lexington, KY. Probably 4th grade, 'cause it was Secret of Evermore and Earthbound that got me into RPGs, and that was 4th grade. Anyway, knew nothing about it, got it strictly on brand recognition, and, uh... it's... one of my favorite games ever although I have no idea why.
Realms of the Haunting - Got this at an HPB in Lexington, KY on the way back from Gatlinburg some November a few years ago. Didn't really know anything about it. Looked cool. THINK we had smartphones by that point so I bummed my mom's for a second to see what HOTUD had to say on it.
Didn't get around to actually playing it for a few years but oh my god what a brilliant game.
Tong Nou - Got this at a now-defunct used CD/game/movie store at an outlet mall in Pidgeon Forge. I was like 17 at the time. This was before SomethingAwful let's play'd it. That was... jarring experience.
And here's a special one.
Captain Comic 2 - Got this from the Fairfield Mall down by Dayton when I was in third grade, and got it home to discover it was missing the copy protection sheet. Couldn't play it till I was in sixth grade, at which point I found a cracked executable, although it turns out that this was, uh, a 'trapped' cracked executable that told you to go buy the game after a certain point.
Eventually found someone with a code sheet to send me ;) CC2's kind of really clunky but, uh, in terms of DOS platformers, it's one I really enjoyed.