Make sure its a Sistema. A Sistema is a Colt-licensed gun, built on Colt machinery to then (pre-WWII) Colt standards. They're made of good steel and are as good as any 1911 made by a Colt factory. All parts are interchangeable with other factory Colts and 1911 clones.
They're available in very good condition for anywhere from $250-$400. I've seen them recently in SHot Gun News for about $350.
Be sure it isn't a Ballestar Molina or Ballestar Rigaud. Those are Colt knock offs, and not bad guns, but few parts are interchangeable, and upgrading or repairs could be a problem. They frequently shoot very well, though.