I can fully agree with the recommendations of the YHA as a cheap way of finding accomodation.
A few friends of mine will spend the end of next week doing the Welsh "Three Peaks", I.e. Snowdon, Cadair Idris and Pen y Fan. With a car to get to the suitable Youth Hostels which make excellant starting points for the walks.
The earlier comments about changeable weather should also be remembered, not only for high level walks.