Megatrain is only useful if you want to travel at obscure times during the week. They never have anything for a Friday evening or a Sunday which makes it useless for weekend trips.
I'm a big advocate of the National Express coaches. I got a Friday- Sunday return to Cardiff from London for £12.
Takes a bit longer but it saved me over £60. They have a wide choice of departure times as well.
I used to get returns to Sheffield for less than a tenner when I was going visit Tim before he moved down. The train would have been over £80

Edit- this is Jay posting
Post edited by owner 22/01/2012 15:43:06