Here in the UK I paid £70 GBP for my first one ($140 USD) in reasonable condition, then £29 ($58) for one I thought I needed spares from in better condition (sold on for a wee profit in the end) and just the other week £5 ($10) for a non-folder, admitedly in a state where pretty much everthing beyond the frame has to go. Come to London and pick one up cheap while you're here!