I'm not quite sure what you're saying here, i.e. what exactly your objection to the structure is.[...]because it is a passive adjective but you are linking it to a particular subject (yourself).
Sure, but I think you can also use it with a specific person. However, I would use a different preposition: "The car is not affordable to me." I'm not saying that's how I would say it, but I don't think it's wrong.It is an adjective that is used with items that can be afforded by people in general.