I even got that blasted Tip Jar working. Sorta.
Alright, to be honest the way I got it working is a total kludge involving Store.MUF, meaning that you can only donate either 15 or 20 pennies, and I think it deducts 10 pennies from that for generating a "recipt" item. (Can't sell nothingness aparently, and minimum item value is 10 pennies.) So donating 15 pennies gets me 5 pennies and donating 20 pennies gets me 10 pennies. And it won't let a 10-penny object cost 25 pennies for some reason.
But still, barely functional is better than nonfunctional I guess... :/