I have a friend of a friend offering to sell me his cheap AR with 2 mags, 2 boxes of ammo and a case for $700. I know very little about AR's but am more comfortable starting with a cheap already built one and he says its half Smith and Wesson and half Olympic Arms gun. 1) does this sound like a decent deal? 2) does anyone have a cheap AR or M&P 15 they want to get rid of for less than $700