Follow up and Cari's value comment.
Level of advertising is a huge factor too. Last weekend I went chasing a Rocketeer. CL listing under garage sale. "sewing machine" was the second fuzzy picture. Nothing to even indicate Singer unless you were a fan. It was in a town of 300. 15 miles away from the nearest stoplight. And the actual sale was a "make an offer" sale at a motorcycle shop. Seller didn't know what he had. All factors in my favor. I made an offer for the 500 in a cabinet with manuals and two sets of cams. He upped my offer by $5.00. Bingo.. oh wait. my GF was faster with her money. Giggle. I won't tell you the purchase price, but it would make many of you groan. Someday I'll have to get a pic of her 500 by my 503.
Leon