My library system has every language Pimsleur offers. I've only bought languages (Thai, German) that I knew I'd use long term. Honestly, for individual learning, nothing beats it. Duolingo is fun, but it doesn't teach comfort with conversation and is awful for pronunciation in most the languages I've tried. Some languages have more high quality resources than others, granted (German has a ton, Thai...not so much), so it's worth looking, but I count Pimsleur among the free resources due to ready library availability.
In fact, I just ordered Mandarin from my library system.