Call your credit card company and ask for a lower rate. If they decline, shop around. You might find a better rate with another card.
Car loan rates are pretty low for those with good credit. Just don't take one of the newer, longer 7-year loans. That could cost you an extra $5,300 on a $20,000 car.
Now may also be the good time to refinance your mortgage. Rates are reasonably low. Opt for fixed-rate loans, not an adjustable one.