I've personally tried out Babbel and it is a solid learning platform. Comparable to memrise but a little more expensive. All these learning apps are great for self study though.
Pros:

• Easy to use interface
• Study at your own pace
• Different styles of learning built-in within the app

Cons:

• Like you said, the price is a little expensive
• Lots of competition in this market, with similar products

I think it is a good program, but I use Memrise because it offers more language and I like some of the tools a little better