If that Monitor Top works, it's definitely worth $100. It's an interesting one, with early coil design but metal evaporator -- a combination that offers the best of both form and function.
$100 isn't bad for the other fridge either. It's a nice size.
If the seller has advised that these items are not being sold for functional use, that could be a red flag unless he just doesn't want to be responsible for either stove blowing up.