Audible.

I've enjoyed my audible subscription. But, the books I buy cost less than the price of a credit, so it's cheaper to buy them with money rather than monthly credits. Hard to explain, but I've taken advantage of it, bought up enough stock for a while, and now cancelled it. It was a good thing, I'm glad I joined for that 6 months.

I really like listening to things and doing things at the same time. Hands engaged on one level, ears and mind on another. It's like I focus better when multi-tasking. Mind less likely to wander when there is already a secondary task going on with the hands. My job is mostly a hands job, just on computer.