Depends on the seller. He may think he's got the only one in a thousand miles of you. But, in reality, 6601's and 6551's are pretty common and easy to pick up (in excellent-like new cond.) for around $1400-$1500 or so (depending on what accessories are included-orig. box, mags, cleaning kit, etc.). Also, all 6601's are not the same. Some will have slab sides, others raised fences. Some will have large front pivot holes, and others, small ones. Some will be ready for mil-spec push pins, others won't. The most popular will be the raised fence, small hole, push-pin type (look for a "weep-hole" on the raised fence just below the ejection port cover...though not all will have this hole). Generally, the higher up in serial number you go prior to the ban, the better off you are on getting all these features.