It's a 20" expert frame. 1 1/8 wheels unless someone just slapped those on its hard to tell on my phone. The last frame... expert 20" like yours that sold on the museum went for $219. That was frame only, in July of 17. There is not a big collector market for vintage mini seats, cranks, wheelsets ect unless for display. They all have weight limits that unless you weigh 80- 100 pounds are useless to most.
hard to say what to list it for. I'd put a reserve on it... see what happens. Some guys will build one just so their son or daughter will have a match to their pro xl, or 24 cruiser