As the previous posters have mentioned; look at the Taurus PT1911 and the Para GI Expert.
I have the Taurus and it's been great. Accurate, feeds everything I've tried and 100% reliable. I've also been reading great things about the GI Expert and would love to add one to my collection.
Check out the Armscor/ Rock Island Armory (RIA) 1911 series.
Link Removed lists the RIA 1911 GI for $339.95 and the RIA 1911 Tactical for $399.99
IMO, the RIA 1911s are better than (reliability/accuracy/fit & finish) the Taurus 1911s and the RIA 1911 Tactical is the best NIB under $500 1911 currently available.
If you wanted to spend a little more, you could always set aside some money in a savings acct( $50 per week) and by the time December rolls around, voila! Personally, I buy most of my guns on layaway at my local gun shop. Right now, I have a beautiful used, excellent condition, with only 50 rds through it, Colt Night Officer's 1911 on layaway and will be bringing it home at the end of July. I got a pretty good deal on it as it was owned by a FFL holder. It's also a very rare gun, (Lew Horton) one of 300 made.