Automatic pay-per-use is nice idea and I want it explored, it just hasn't been built yet, so it's hard to predict how that will factor in. My point is that it's clear who has the incentive to pay for relays - creators, by running a relay or by outsourcing it.  

 There is an option on hablanews, fountain to split income with selected accounts. That's the basics for sharing your $5 a month paid relay fee across a. bunch of relay runners.