Stonehenge Tours
As my tita mentioned, a train + bus ride to Stonehenge can cost £40. Here are tour package alternatives, although I am actually pretty opposed to joining a tour as it does not give you the freedom of time. Anyway:
1. Windsor, Stonehenge, Oxford
http://www.sightseeingtourslondon.com/select-windsor-stonehenge-oxford-tour-p...
2. Stonehenge Express
http://www.sightseeingtourslondon.com/stonehenge-express-tour-p-229.html
3. Windsor, Stonehenge, Bath
http://www.sightseeingtourslondon.com/windsor-stonehenge-bath-tour-p-38.html
I really want to go to Bath. Yeah. That's all.