Hello Katya, have you tried following any of those two tutorials ?
https://support.appdrag.com/blog/78-Zapier-integrations.html?category=1.html (zapier integration on appdrag)
https://zapier.com/apps/appdrag/integrations/stripe (stripe integration with zappier-appdrag)
Hope it helped, have a nice day

Hello Bogdan,
Yes you can create your own memebership feature with some pages only accessible to members.

Here's the link for tutorials about that:
https://academy.appdrag.com/.

Hope it helped