In order to teach the girls how to budget money we made a budget form that gave their monthly allotment (I think we said about $1500 or so) with about 7 or 8 bills as well as their allotment in the form of Monopoly money.
Tithing was listed first and of course we had them figure out 10% of their allotment. Fast offerings was next and we explained that they could give as much as they felt they could afford, but that they should try and be generous. Some girls gave $10, other $50. As for the bills, some of the amounts were set, like rent and electricity and other amounts they filled in after they paid their bills, like grocery and spending. In the end all of their categories should have added up to equal their monthly allotment. It was surprising to hear some of the girls talk about how fast their money was going!