Transport Tycoon
Transport Tycoon is another game I picked up in the bargain bucket, and went on to spend far too much time playing! It's an excellent simulation game where you build roads and rails and buy lorries, vans, trains, ships and aeroplanes to travel between your stations, ports, etc transporting stuff to make money.
A number of limitations from the original game are addressed in the TTD Patch: http://www.ttdpatch.net/
But a written-from-scratch remake is even better: https://www.openttd.org/