https://statetable.com ~ $30/month from donations covers my Digital Ocean bill for the month. I'm also trying to get some sales & affiliate revenue going with athletic wear designs on Zazzle. Starting with a niche to get rolling then probably expanding to more general designs. The biggest problem I've hit so far is their fulfillment times & prices.
Any revenue from the ad?
It's pretty unobtrusive up in the corner there. I'm sure it suffers from banner blindness. But I don't want to load the page up with ads. It's a tool for other devs, not really a revenue source. But the donations are nice.