If you're on a low income you can do the NCT classes for lower than the advertised price - I contacted the person running them to ask, she was lovely about it and said we could pay a minimum of £20, we chose to pay £80 because we felt we could afford more than the £20 and the NCT is a charity after all. I really thought they were invaluable, our NHS ones were
awful. There were only 2 sessions and about 30 couples there so no chance of meeting anybody and becoming friendly with them really, it was too impersonal. I was told there were other NHS classes though run by our hospital, like a waterbirth class, a TENS class and a relaxation/breathing class, I only heard about these when it was too late, but again they were all one-off sessions and I don't think that is very useful if you are trying to meet people.
Why do you want to go to classes? To meet people, learn about birth, learn relaxation techniques, learn about babycare? If you can give us an idea we might be able to suggest less costly ways of doing things

Ask your midwife what antenatal classes are available for you, she should provide you with a list and register you for the ones you want to go to.
We had 4 classes of 2 hours each, plus a breastfeeding class (2hours) and a car safety class (1 hour). all for free.
It was good to meet up with local people who are also having babies.
I quite enjoyed the classes too, I thought they were well organised.
We also went to the NCT classes, 8 classes of 2 hours so we were able to cover a lot more stuff and we have all kept in touch so far. (babies due in june.)
Yes active birth yoga lamaze just google antenatal classes in ....shire and it will come up with a list
You will probably be offered some at your local Drs/hospital. I went to those but they reaaly weren't much help to be honest. Your midwife might be able to tell you what is available in your area. HTH
Am new to all this and won't need them for a while but just wondering, apart from the NCT ones are there other classes which aren't so expensive?