My credit is bad But i want to buy a used car for my son Does carmax can help me to get a used car for my son

Yes. But their rates are insanely high. I have a great score of 750 and they wanted 14%!!!!! I went to my credit union and got the loan for 2.25%. But yes, you will get a car but you will pay handsomely for it

The rate will be high Try DriveTime

I'm sure they will help you but at very high rate..

Go to any credit union and open an account. They will take you as a member even if you do not belong to their field (i.e., Financial Credit Union will take you even if you are a mechanic).

Like you said your credit is bad, doesn't matter where you go your loan rate will be high, depends on your credit. But yes you will get a car.