There are many short stories where a yukkuri gets money, and then gets mugged by other yukkuris/anons with "happy end~"s .
So more stories then developed a special currency yuro (Euro, getitlol) for the yukkuris to use. As usual, antics and much "happy end~" and JUSTICE resulted.
>>Well, shithead though she is, Yun Donuts' Marisa did actually pay for her donuts...
If I recall correctly, the shitheads paid, but not the correct amount. I'm thinking that yukkuris have an idea of what money does and that it gets them tasty-tasty~ stuff, but not how it actually works. Kinda like sweets. They love the stuff but have no idea what they're made of.