After singing up for Tumblr and being sad that they're not yet (and might never) federate with Activitypub I started digging around fedidb.org and found out about micro.blog.
It's very similar to Tumblr but federates with Mastodon allowing you and Mastodon users to follow each other. You show up as, my example, jezebelley@thefrequency.blog to ActivityPub users (I had to reset my profile after switching to a custom domain so if you check it now there won't be any posts. Before I reset my blog was federating perfecly). If you make a blog post of 300 characters or less it gets tossed right into your federated profile page with no click through necessary. Longer posts will be shown along with the rest on your blog domain proper (I.E https://micro.blog/jezebelley)
The catch? It's not free. $5 gets you basic membership which allows blogging and photo uploads. Non animated only. $10 gets you premium which allows for video/gif hosting along with podcast features if you're so inclined.
You're also allowed to bring your own domain, in my case https://thefrequency.blog, to host directly to your custom corner of the web. It's very simple to setup. If you want to go the super easy route you can sign up directly for a domain in the micro.blog settings with a major downside being you get no registration privacy meaning your URL is subject to WHOIS indexing. A major nono for privacy. I recommend name.com registration independent of micro.blog as you can pay $5 for their privacy package and then import it.
Anyway thought I'd give you all a heads-up for a great Tumblr style option right here on the fediverse!
Is the paid part just for using their server? Like can I setup my own micro.blog instance and have people sign up for accounts for free and be able to post videos?
I don't think you can self host unfortunately. You can bring your own domain but they host the data.