Well, the going rumor is/was that the guy that owned that store had some kind of in with the Ghermezian brothers (or was actually related to them somehow). Because of this he's been able to keep his store in that location in the mall (very prime, right by the ice palace) and pay a minimal fee for rent.
Let me take all you Edmontonians on a little trip on the way back machine through the history of West Edmonton Mall and video game stores. Back in the early 80s, there were 3 video game stores in the mall originally, "Play Me" (which was called something else at the time), and 2 locations of a store called "Electro T's". From what I've heard, all these stores were owned by the same person (I believe the father of the current owner of Play Me). They all dealt primarily in PC games, but also sold console games (atari, intellivision, coleco, etc... I believe Electro T's was already closed down before the Nintendo era). Anyway, eventually the 2 Electro T's shut down, and we were left with Play Me as the only video game store in the mall.
Around this time, another Edmonton video game store chain opened up in the mall, "Trade and Play", which would later have its name changed to "Virtual Reality". In talking to a guy that used to work at this store, I heard that when Virtual Reality was in the mall, all the owner of Play Me ever used to do was give them hell and try to get them to move farther away from his store, leave the mall, etc etc. I'm not really clear on the particulars here (mostly because I can't remember the story I was told), but eventually Virtual Reality shut down, and again Play Me was the only video game store left in the mall. Another rumor I heard is at this point, the owner of Play Me made some kind of deal with the mall that he would be the only "video game" retailer allowed in the mall.
Now, while this might sound sketchy and strange, keep in mind that West Edmonton Mall, a huge market, didn't get an Electronics Boutique/EB Games/Gamestop until 2010, when even smaller market malls (like Sherwood Park Mall) have had one for years.
So, it seems like whatever exclusivity deal the guy had has now expired, and he's been forced into the position of selling his games (mostly) for affordable prices, instead of crap like selling "Castlevania: Symphony of the Night" for $79.99 used.
I think the biggest problem with "Play Me" and their prices is that they've had such a long run of being the only real game retailer in the mall (besides Zellers and Radio Shack), and felt that they didn't really need to worry about their prices. Also, I get the feeling that the owner doesn't even really like games very much, nor have much interest in comparing how they should be priced, etc. This is why you'll almost always see games from popular series (like Final Fantasy) retaining crazy prices, where rarer/non-popular games (eg, I picked up KoF 12 there for $19.99 used soon after it first came out.. where the normal used price was around $54.99) have completely unpredictable prices.
Take all of this with a grain of salt. Some of it is based on a conversation I had with a guy that used to work at the previously mentioned "Virtual Reality", and the rest is really based on rumor and growing up being an arcade addict/video game freak in Edmonton and noticing/remembering most of these things. I'm not really sure how true it all is, but there certainly must be some reason he's been able to keep that prime retail space when the traffic in the store is so obviously low (about 10 years ago the place was trying to change their business model and were selling a ton of used CD's/VHS tapes in hopes in bringing in more customers).
I still poke my head in there every now and again. Occasionally they will have some pretty decent deals hidden among all their overpriced junk. Scouring their used games sometimes pays off (as like I said, the prices can sometimes just be wonky... and "wonk" in your favor). Another good thing about "Play Me", is that they will generally put stuff out on the shelves as soon as they get it, street date be damned (they had FFXIII out 4 or 5 days early).
Honestly, my best memory of "Play Me" was back when Legend of Zelda: A Link to the Past came out for the SNES. Every single store in the whole city was sold out of it on the release day (or, they didn't have it in stock yet, knowing Edmonton), and "Play Me" was the last one I called. And they had it in stock! And they held it for me! So... no matter what people say, I have fond memories of them for that. Ahh the good old days.