http://www.bob-oracle.com/1911buy.htmYour inspection in the store will tell you basic obvious things, but shooting will really be the final arbiter of reliability. Try to focus on stock, factory guns that have not been modified in any way. A deal that looks too good to be true in a pawn shop probably is too good to be true because 1911s fetch high prices.
One word of sage, ominous truth about 1911s from a man who knows is that people who buy low-end 1911s very frequently pay an extra $500+ to have them tuned to their liking within six months. 1911s and "short on cash" doesn't mix very well unless you're willing to put up with some hassles and refine the gun over time.
If you set your budget to around $600 and look at the new Taurus if you're a risk taker or a Springfield Mil-Spec if you're not, then you can get a good new gun without adjustable sights. If you think you'll want adjustable sights, then just wait and buy a gun with adjustable sights in the first place. If you spend too little money, you'll end up with something you don't want to use.