I've seen some OK buys in Pawn Shops, but you do have to be careful. The Pawn Shop owners know instrument values better than any of us. Check all instruments, amps and effects out carefully before buying, and find out the return policy if something doesn't work.
I see a lot of Squier Strats in Pawn Shops, and that is how I gauge prices. You can buy a Squier Affinity Strat new for about $130 and a Squier Standard Strat for about $220. If I see a Squier Strat marked well above these prices, I believe that you should be real careful in that shop.
We have several pretty good shops in this area - some have a lot of instruments at prices that you can swallow. A few days ago, I saw a '93 Gibson ES-335 in great condition for (I think!) about $1400.