Torii is free, and can be found here. It’s an application, so you don’t do your reviews on a browser. I’ve had good experiences with it. A similar free service which is exclusively browser-based is KameSame.
Bunpro has a 1-month free trial, which is super worth it in my opinion. You can (although with some difficulty) go through the entirety of the JLPT N5 grammar points in that time. Plus, I think they still have that discount so that monthly subscriptions are just $3 — it’s an absolute steal, in my book.
some others will probably come evangelizing* about Kitsun eventually, I expect. I used it once, but it wasn’t really to my taste.
*just a silly joke 