The old Kenmores are some of my favorite vintage machines. I buy them from the thrift store for up to $35 each. Then I'll get them all serviced up and sell them for $50 to $100. Your machine doesn't have any built-in stitches (it uses cams to get the different stitches), and it is a flat-bed instead of a free-arm. It does have a standard low shank presser foot, which is better than the super-high shank. But I think the most you could get for it would be $65.
The 158 series Kenmores were made by Jaguar.