However you want. You would have to pay completely out-of-pocket. You might want to ask your dentist the cost of x-rays to be taken so that you are aware of your responsible portion. Most forms of payment include cash, credit card, health savings accounts, third party health cards (care credit), etc.
Out of pocket. Many patients pay for them out of pocket. Especially if they need several types and insurance will only pay for one type. A good dentist is going to be concerned about making an accurate diagnosis, which in part relies on x-rays. Hopefully you can obtain the funds to pay for this important service that may diagnose something that could lead to a big, expensive problem.
Pay for it yourself. Pay for it yourself. Usually they are not very expensive. They really help the dentist diagnose the condition of your teeth.