Well, credit is based upon how you pay your bills, not how much money you have. Even paying your utility bills on time is part of your credit rating. Often power companies will refund your deposit if you pay on time each month for year. That means you have good credit with them.

You can have a credit card without having money, and use it to make good credit. Open a small savings account. Then, at the same bank, get a secured credit card. This will give you credit up to the amount you have in savings. (You won't be able to withdraw your savings though, only use it for securing your card.) Then, if you charge just a small amount each month and pay it off on time, you will build good credit. The amounts don't matter as much as how you pay, and how responsible you show you are in paying your bills. (Once you create good credit in these ways, you can apply for a regular charge card, but you still need to pay it off monthly to maintain the best credit rating.)

Just as examples.