I have found a brand new way to save money on rail travel, since MegaBus.com no longer serves our area (and that used to be £1.50 per trip to London sometimes, we saved lots of cash).
The site is called:
I found I could book each leg of my trip separately, which is the only annoying thing as I would have liked to do it all in one go like a 'shopping basket'.
Still, I only paid £5 one way to London, and another £5 for the return trip the next day. Plus this £10 includes booking fees and posting to my home. Technically the tickets were £3 each though! The service was very quick too, tickets arrived within 3 days of my online order.