I think your first order of business is to see if your vendors will accept credit cards, and what kinds of credit cards, for your purchases. Even if one or two of them will, it should be possible to meet the minimum spending requirements for initial sign-on bonuses, some of these cards.

Some of your vendors might take Visa but not American Express, for example. Or, they might charge an extra "convenience" fee for using a cc vs. paying by check. (That fee would be to compensate for the extra processing fees a credit card charges, which is only fair).

You would need to crunch the numbers to see if the extra miles and points you earn would be worth the extra convenience fees those vendors might charge you.