I got myself a Mega lower and a Stag flat-top M4 upper for around 730 buckaroos. ColemanTyler.com for the lower and AR15sales.com for the upper. Both are high quality parts and came with some extras (non-molly chrome barrel, rear flip sight, RRA trigger, collapsible stock, M4 barrel). $600 bucks for a quality, but very basic AR15 is possible... but why not spend a little extra and get a little extra?