I have Babbel's lifetime membership. There are two parts, the automated lessons and the subscription live instruction that you have to pay extra for. I've stuck to the automated lessons because I'm poor.
I've had trouble sticking with it. I think they move on from some concepts too quickly (verbs, mostly), so you may want to invest in a notebook. They have a nice review option that's supposed to help you remember words more effectively, and you have options on how you want to review.