Welcome to Shopify Community. My name is Olivia and I work here.
Thank you for sharing your question, I definitely have the answers you are looking for. In fact, I answered a thread similar to this where I listed options for a multi-vendor marketplace like store. Check out that post here.
Focus in on paragraph 3, where I discuss the following:
For starters, you will need to make sure you are at least on the Basic Plan or higher. I encourage you to browse through the different plan options too, but having the online store feature is the only requirement per se.
From there, you can choose an app add-on from our App Store. To make things easier for you, I shortlisted some options you can browse through below:
Check out the full thread for an additional recommendation from a Shopify Partner as well.
Let me know if you have further questions or comments and I'd love to chat more.