Is there a way to get a forum like SQUARESPACE Forum on my site?

My website is about making a community and I would love if viewers who sign up to be able to create their own blogs OR a really inexpensive forum plugin like the one Squarespace uses for theirs. I don't have any money to spend $89 a month on circle plus the money I will be spending on this yearly and the money I spend on putting  my art on Etsy. Is there a way to do this? Can Squarespace just make is so anyone who makes an account or membership on your site can post a blog? If not I'm lost and I don't know what to do and will have ended up wasting so much money that I don't have.