A fresh coat of paint makes an old car feel new again, but it is a massive upfront hit to your wallet. You are looking at around $2800 for a quality job that actually lasts.
Timing matters here. Shops are often dead in the late fall or early winter, which is when you might find a better deal on labor. Avoid the humid summer months, as moisture can ruin the finish before it even cures.
That 15-month window is a deadline, not free money. If you have any balance left after the 15 months are up, you will start paying interest on the remaining amount at the standard rate.