My dds go to several art clubs at various prices. We don't mind paying as it's a major interest for all of them and they spend a lot of time doing art, but some classes are much more worth it than others.
13yo goes to a free school club at secondary (not much use for you), art students run it I think and I don't know much about that one.
All 3 (13, 12, and 9) often go to a 2 hr Saturday club which is £5 for 2 hrs, in a local art gallery, with "proper" artists and drawing on the current exhibitions. That's really good, it's usually about 6 children aged 6 up and quite varied art.
Then they all 3 go to a whole day art,craft and sewing club once a month on Saturdays, that is £5 for the day and they absolutely love it, it's a sort of juvenile Bitch'n'Stich, but it's run by someone who's retired so not bothered about the money. I don't see how she can make any money as she often buys them lunch out of that or takes them to art fairs.
They go to various other art classes too, in small local studios or art galleries, on a one off basis, we often pay about £5 a session, sometimes £12 for a 3 hr session but those are often no better than the free or cheap ones, so we've found little correlation between cost and quality of the class, but we really look for classes that are a bit more sophisticated than basic stuff as my dds have done lots of art and I look for classes that teach them something, also ones that introduce them to various art styles and artists. How to look at pictures, etc.