Yep, I do do custom stuff! Basically, a lot of the illustrations can be put on the ring that I already have made, if you request it. That is no additional charge. But if you want something custom there is a charge for the illustration, and then a charge for the ring.
Well, if it's for the ring it's going to have to be quite simple! So that means it wouldn't be too much. So probably anywhere from $15-25 just for the illustration. But if you want to let me know what it is you're looking for I can give you an exact quote.