Memrise is 100% free. It comes as an app or a website (http://www.memrise.com/), and it has a multitude of languages to choose from. I've been using it to brush up on my Mandarin vocabulary, and it has a lot of different classes just for that language. It's definitely worth checking out, and it's a really useful tool.
My name is Sam, and I want to be fluent in Chinese and Russian! I just got accepted into the University of Florida to get my bachelor's in Chinese, so I'm working on the first one, and after I get a little bit more fluent in Chinese, I'm going to start taking Russian classes! So hi there, Linguaholic!