enough credit card programs out there provide cash back (1-5%) on purchases, for no annual fee. that ought to make using it for a monthly purchasing conduit ideal (your real cash can be collecting interest between monthly payoffs, and your transactions get a nice 1-5% haircut usually at the end of the year).
If you consider your credit card to be a no-fee (or low-fee) payment mechanism that aggregates your monthly expenditures into a single bill, you can have savings theoretically (though in reality, probably not usefully) appreciating over the course of the month in a bank account, and then pay the bill for your expenditures at the end.
This simple money management technique reduces fees paid for ATM access, allows your assets to maximally appreciate, and builds up a very solid credit history. Credit Cards and Lines of Credit aren't evil; they're useful, but they're not hard to use in a manner that will bite you.