I'm glad that the Game Exchange chain is in my area because they sell games at reasonable prices. Although each store is independently owned, it is very corporate (which is good for retro gamers). Their prices are set at a home office, and the franchises simply price according to the computer. The stores don't price individual games according to current market value, which makes for some great deals.
Nearly all N64 games are $15 or less. I bought boxed Paper Mario & Mario Kart games there recently. The most expensive N64 game I've seen there is Conker's Bad Fur Day for $25.
Nearly all Sega Genesis, Sega CD, & Saturn games are $7.95 or less, and many are $1.95. I bought a complete Sega CD Snatcher for $7.95. I've seen only one game priced higher than $7.95.
NES games have the widest range of prices, and some are overpriced. However, I've bought games such as Mike Tyson's Punch-out for $7.95, and most games are less than $5.