Originally Posted by MacCool

If you're talking about red dot sights, for low round-count, range use where maximum reliability isn't a factor, look at Primary Arms. I can't vouch for their quality but the store itself has good customer service and the owner is reputed to be a stand-up guy. He makes no bones about these being budget optics. I don't know how long they'll stand up to 5.56 recoil or how accurate they are...reviews are mixed as they often are on these Chines imports, but they might meet your needs. The Vortex sights have a little better reputation and would be worth considering.

If you're talking about 1-4x scopes, Vortex, Bushnell and Nikon are supposed to be pretty good for the money. Vortex Optics