Those are great little amps! I bought one brand new to go along with my silvertone guitar @1963; 60 years ago. Yikes! Loved and miss, to this day, the Sears catalogue. I think it was about $95.
I gave the guitar and amp to one of my brothers when I gave up guitars for a few years. He had it for a long time. A few years ago, I told him they were selling for $600 to $800 on ebay. He was surprised.
I asked him if he still has it? He said he had a pipe burst a few years ago and it got wet. How bad I don't know. He chucked it.
On a side note, I also all but gave him a 1967 Pontiac GTO, mistake #2. He didn't have it a month when he totaled it.
Tom