So, I'm going to London next week and a friend of mine will be in Manchester and I was wanting to visit but not sure the best way to get there. He said the train tickets can be very expensive if you don't pre-book them but I'm not sure I want to do that either because I don't know for sure when I'll be there and when I'll be able to leave. Also, do they travel at any time because I'd probably be coming back to London on the later side. I really don't know much about this; all I know about is the tube which I plan on using the most. Any tips on where to get tickets or what to ride would be greatly appreciated!! Thanks