<prompt> Human: Im going to get a car on Monday, I have about 15 to put down but will have to finance the rest. I was hoping to save more but my 19 year old car is dead so I cant wait any longer. I have a credit score of 680, not great but not terrible. My SO is going to help with payments because we live together, share bills, and will both use the car. However, he does not have a credit score. He wants to cosign on the loan so he will finally have a credit score. Will that raise the interest rate I could be approved for? Would it negatively impact my credit?  <response>: Theres not upside to you by including him, and he could build credit with a credit card. 