And the issue of converting the Puch back to gears? Better to find a new(ish) bike?
The fact that I bought a one year old Tiawan framed 'mountain bike' with low end Shimano gears from a company that rents to tourists to cruise the inner harbour with ~16 days use for $200cdn should give you a price point. I have stripped the gears off and glued the seatpost in because it's intended purpose is a commuter for less than the price of a good lock.
It would have been good enough for a couple of weeks of casual trail riding as it was.
Decisions, decisions.