Bhkyte is correct, it is a very underrated bike, very capable and robust but heavy. The weight is probably a factor of the components. Your bike has been retrofitted with V brakes which will be a big improvement on the Dia-compe cantilever brakes it had originally. The groupset is ok, the crank is SR Sake ovaltech which is original and has some value to people who like oval chainrings. I can not give you an idea of value on the US market because I an in the UK. I own a Rudge Bi-frame which is exactly the same bike but marketed in the UK under the Rudge brand. I paid £50, they often sell for between £50 and £80 here in the UK. I have owned other full size folding bikes but the Montague/Rudge has been the best so far and the most compact when folded.