How can I tell my friend that I don't want to do roller skating lessons anymore?

Back in early summer last year my friend said that she is really interested and keen to take up roller skating and she asked me if I would like to join. Back then I was curious and as I use to roller skate as a kid I thought why not dig up an old hobby. So we decided to take lessons that would take place at a roller rink that is a 50 min drive away (that's the nearest one) and the lessons would take place at 9 am on a Sunday.

Back when we decided to do this I didn't think anything of it, we take turns driving there and the lessons are £5.

But now I'm not enjoying it. Getting up at stupid a clock and driving for 50 mins on the motorway on a Sunday is not something that I want to do anymore. £5 a week for me, as a student, is adding up to be expensive and I could save this money for something else like food or rent.

I just don't know how to tell my friend that I'm not interested anymore. Every week she is like "can't wait for skating" or "I'm glad we do this skating thing, gives us a break from uni work" or "I'm really enjoying skating" and I just sit there thinking I'm not enjoying it at all. I mean I was at first but now not at all.

With her expressing how much she loves skating I just don't know how to tell her that I'm not, I don't want to hurt her feelings!

What should I do should I just tell her?