Is it worth it to pay for Duolingo? I started using it to learn Spanish for no reason than to have something mildly productive to do with my phone.
I believe you can still activate Duolingo for schools ('make classroom' or something like that) and get the benefits for free. By benefits I mean: no ads, unlimited re-tries, and no cost to final tests ('legendary' just sounds stupid). That said, Duolingo is better at supplementing learning than teaching. It explains next to no grammar, so it's worth to look-up lessons on duome (already found you Spanish) or other sites. Personally, after finishing a couple languages there, I went from being a huge fan to seeing it as jumped-up flash cards. Also, there are many, many stupid sentences inserted there solely because they're easily meme-able and act as free advertising. For instance, their Latin course consists mostly of sentences about drunken parrots. In day-to-day living language situations, Duo is more useful than "angry drunken parrot stole urbane young man's cookie" is to studying classics, but I wouldn't want to imply or suggest it's more usefull than taking an actual class.