My dad keeps offering to cosign a car loan and I don't know how to say no without it turning into a whole thing at Thanksgiving | Awkward Family Talks - Rigidtalk
Read a thing once where a guy let his mom cosign and then she held it over his head for YEARS every time he made a choice she didn't like. That is the real cost here, not the money. Just tell your dad you want to build your own credit and keep it short, because explaining too much gives him stuff to argue with.