Keeping your car clean through rain and snow is a losing battle without the right gear, but those custom-fit floor liners usually run about $250. Buying them right before the wet season hits means you will pay top dollar, whereas shopping during end-of-summer clearances or holiday sales often knocks the price down. Grab them when the price is softest so you are not scrambling when the first storm arrives.
When you are ready to buy, separate the haggling from how you pay for it. Dealerships and parts counters will try to bundle accessories into your service bill, but you want to negotiate the price of the liners on their own first. Once you have the best price, you can decide how to handle the cash flow without letting a salesperson mix the two together.
Just remember that the intro window is a hard deadline, not free money. If you still have a balance left on the Citi Simplicity® Credit Card when the 18 months are up, interest charges will kick in on what is left.