These are the two Gaming Generations i've been to. They're still open and legitimate. Other locations are in the spoiler.
Gaming Generations is a "chain" in Wisconsin/Minnesota, but I believe each store is locally owned, sets their own prices and manages their own used inventory. The prices are different from store to store, so don't write them all off if you've been to a bad one.
I really love the Stevens Point location. They get a lot of weird import stuff (lots of PAL DS for some reason). It's also nice when the owner says "Shoot, this one doesn't have the manual.... Do you still want it? I can knock a few bucks off". Most places I shop don't even know that they're supposed to have manuals. They had a sealed Bandai Pippin game in there once, which blew my mind and kept me coming back.
Gaming Generations
135 Division St
Stevens Point, WI 54481
(715)254-9990
The Wausau location is okay. They seem to focus a lot more on selling custom controller/console skins than games though.
Gaming Generations
3140 Rib Mountain Dr
Wausau, WI 54401
(715)843-4263
Johnny Cee Cards
536 Grand Ave
Schofield, WI 54476
(715) 843-9632
This is the closest store to me with any kind of inventory. The prices range from "Holy shit! $125 for a sealed copy of Steel Battalion w/ Controller!?!" to "Holy shit! This PSP game is marked up $70!" They get some neat stuff now and again, but its pretty few and far between. They handle NES repro carts on occasion, and don't mark them as such. It's only for games without a US-release, but it still bothers me. If you want a fairly legit looking boxed copy of Mother, though. This is the place to get it that isn't the internet.
Toy-Riffic
2919 Mall Dr # B
Eau Claire, WI 54701
715-832-5060
I love Toy-Riffic. Unfortunately I rarely get to Eau Claire. Tons of games. Tons of weird/rare stuff. Incredibly nice and cool staff. No bathroom. Last time I was there I sat in the store talking games with the clerk for about an hour and a half, finally I felt like I was going to piss myself, so I had to leave. Prices can sometimes be a little high, but plenty of good deals to be found too.