When I watch for "Dashboard" machines, they are often in the $75 to $200 price range on eBay. Moer in line with $25 - $75 on the local Craigslist - with the occasional dreamer. When it comes down to pricing - older straight stitch machines sell for the least amount.
Start watching older Viking, Pfaff and Bernina, if you think the Kenmore are over-priced. However, in my 2-3 collecting, I've rarely seen decent Kenmores in the $20 range.