Prices are dropping fast in the space industry:
2001 - first space tourist paid $20 million for 1 week
2006-7 - people will be paying $200 thousands for 3 hours
2020 - ?
2040 - ?
If they get the "Space Elevator"
http://www.isr.us/spaceelevatorconference/aboutSE.html idea to work, then it be as cheap as normal earth destinations...