To answer the last first, I greatly prefer physical CDs, because then I can play them in the car as well as at home.

I really don't know what the going rate is there. In the US, a "commercial" CD normally costs between $15 and $20 in a music or book store. That would be about £9.5-£13. Sales tax of 7% is on top of that, and that varies by locality. I expect to pay $10-$15 if I buy directly from a performer...normally at the upper range.