Donna, I've bought a lot of different sets that included some blackside to put together what I've got. I'd never consider paying $127 for a set - and it's likely no one else will too. There are always some dreamers on eBay hoping for someone with more money than brains to come along- or someone with a lot of money who does not want to bother waiting around for a cheaper item to show up.
I don't think Singer ever sold a full blackside set. To them it was just the updated finish, nothing special. They just did not stick with it.
I watch attachments on eBay constantly, and there are some "buy it now" that have been relisted over and over and over again.