I've decided to start small.
Setting a goal about 32k, which is somewhere in the $25 ballpark, I've decided if I reach that then from then on I'll give the highest ranked supporter per month a free sketch of any one character.
Then go to a higher goal, say 50K, and expand the free sketch prize to the top 3 supporters per month~
I don't really have the time for bonus comics, but giving something small back to my supporters is good ouo