I'm wondering something similar. I was hoping to set up a site where customers can pay for individual online workshops, but Squarespace doesn't seem to offer this. It's either a fixed fee for all video content you upload or a subscription to it. Unless you set up multiple Member Areas.
I find it really complicated and a bit long-winded if I'm honest, and I'm concerned customers will turn away if there's too many barriers for them accessing my work!