i probably was a bit mean to say 'suckers' (apologies) but I just find it daft people are paying what is actually quite a lot of money when pretty much the same thing is happening for free at the same time in the same building!
You always have to factor in what people are paying for. I.e. it's not just a class.
For me, it was worth the money because ...
My NCT class was doing it, it was a good opportunity for us all to hang out. For whatever reason there was more appetite for this class than any other among the group.
All the free classes in my area were oversubscribed, thus requiring me to queue in advance to get in. It was worth it to me to pay money to avoid this.
BS introduced me to more new ideas to try at home (songs, rhymes, activities) than the traditional rhyme time classes. I'm a novelty junkie and get bored easily so I loved this.
The class was more sociable than other classes and I made more mum friends there.
I think everyone finds the activities they (and their baby) enjoy. For what it's worth, I trialled monkey music and hated it, thought it was a total rip off. It's just what works for you.