i have some cavities and i dont have insuarnce?

It depends on the dentist, but dental and health insurances are different. You'll have to discuss with your dentist what your options are. Most will let you pay with a credit card, some will allow you to make payments directly to their office. You say your credit is bad, but it doesn't hurt to at least try for a credit card. There's one called care credit that is specifically for medical use only so you don't have to worry about splurging at the mall and not being able to pay it off. Just look it up online or ask your dentist about it.

Most dentists charge around $300 or so per cavity. If you need a root canal, expect to pay around $2000 for one.

You should look into a discount dental plan. It's very affordable, there isn't a credit check and you can save a lot of money on your dental expenses. Taking care of your teeth is very important both for your health and your self esteem. In these difficult economic times we are all concerned about the cost of things and discount benefit plans are a great way to take care of yourself and save money at the same time.