Please help. I need your advice.

What do you think is the cheapest way to travel considering the following itinerary?

From Brussels or Liege
To Montepulciano (or Florence or Pisa)
Roundtrip
Arrive in Montepulciano Sunday 29 August, 2004
Leave Montepulciano Saturday 4 September, 2004

The only options I have in mind at the moment are:

Ryanair (92 euros roundtrip Charleroi – Pisa)
Train (too expensive for me to remember )
Hitchhike (how safe would this be for women traveling alone?)

Any tips or info you could share would be greatly appreciated.

Have a nice day.