I pay for one-time relays wine is too expensive for me on a monthly but one-time pay I have done. If you were able to send a note monthly to users I bet they would assist until the market becomes competitive.
Discussion
Interesting, could work short-term as you suggest. Not sure if it would be very effective but could be worth a shot before longer term solutions can take its place. Generating and sending notes to such a list should not be too difficult to implement at least.
I find the ask is the hard part.
Try something like this month relay cost X
X/ relay users= sats
If you can compensate for yourself and a friend it would greatly appreciated