Micropayments have been the holy grail online for which everybody from the core web protocols working groups, to IBM to Ted Nelson's project Xanadu have been searching. It's a tricky one to solve, but with the emergence of cryptocurrency tech, there seems to be new hope.

I'm currently involved with a project called SatoshiPay (https://satoshipay.io/), which tries to solve just this headache by enabling micropayments (down to fractions of cents) from a Bitcoin wallet that's created automatically straight in the browser. Still early days, but I believe this could be a user-friendly solution to the micropayment problem.