Free will in my view does not equate to the power to change your life's circumstances. It dies mean the power to choose or even not to choose. In my view free will is more the way you are free to respond to life however you like. Life is happening regardless.
Karma in the basic sense is no more than the "law" of cause and effect. Never in my view was it meant to be the punishment or reward tool that spans lifetimes.
Its simpler than that. You know what makes you temporarily happy. so you do more of it to be happier. simple cause and effect.
With Love
Eelco