How much over an invoice should you pay for a car?

Excuse me, but could you please clarify the question a bit further? Are you asking about the appropriate amount to pay over the invoice price for a car, perhaps as a negotiation tactic or to account for additional fees? Or is there a specific scenario you're referring to, such as purchasing a used car from a private seller or a dealership? Without more context, it's difficult to provide a definitive answer, as the appropriate amount to pay over an invoice can vary greatly depending on the circumstances. Could you please elaborate on your query?