If you’re a collector who knows the rarity of items in specific fields (you can spot an in-demand out-of-print DVD, for example), they’re not bad. I’ve picked up some rarities at pawn shops-- DVDs and video games usually-- which have been difficult to find at affordable prices on eBay or in specialty shops.
Similar to norinew, I’ve found pawn shops are willing to haggle or make deals, especially on an item that’s been sitting around for a while. I picked up a nice laserdisc player that usually goes for $100 on eBay (and was marked that much in the shop) for $25, and a friend wanting a cheap guitar had his eye on a specific one which had remained unsold for a couple of months, and bargained his way into getting a practice amp, guitar case, cord, tuner, and replacement strings thrown in for free. He ended up selling the amp off later on for almost as much as he’d paid for the entire package.