There's also the 16-25 railcard available. I think I paid about a tenner for mine when I was in that age group, but that was discounted when I was a member of the NUS (just as important to be in a union as it is to have a railcard ).

I've done Manchester regularly lately, and I quite enjoy the trip over there. The TP Express is a bit of a pain with all the stops between York and Newcastle, but it's quite quick between York and Manchester. I always feel like you have to watch your back in Manchester a bit more to other places though. Oh, and stay away Salford.