If you want to go to Alaska cheaply it is not that hard. There is a 'backpacker's shuttle' that will take you from Anchorage up to Denali NP pretty cheaply, once there no car is needed if you are into camping.

My Favorite has been Costa Rica. Busses can get you anywhere from San Jose, and food & hotels are still near third-world,no, 'developing nation' prices. Just don't expect hot water for $10/nt.