When a service contract is sold with a car, the seller often asks whether you want to pay for it in cash or add it to the loan. That single question can change the total more than most buyers expect, because the contract price and the loan cost are separate lines that both end up in your future payments.
Where the extra cost comes from
A financed contract is a loan on top of a loan. Each payment covers a share of the contract price plus whatever interest the lender charges on that share. The interest runs for as long as the loan does, so a contract financed over a long loan can cost more than the same contract paid outright, even though the contract itself is identical. Read the loan disclosure for the interest rate, the total of payments, and the finance charge. Those lines tell you what the contract really costs you.
Questions to ask before you choose
Ask the seller to show the cash price of the contract separately from any amount added to the loan. Ask whether the contract can be paid in full at signing, and if so, whether the seller adds any charge for that choice. Ask whether the loan allows early payoff without a penalty, because a buyer who pays off early needs that answer in advance. Ask what happens to the financed part of the contract if the car is sold or the loan is paid off early, and get the answer in writing.
What drives the cost up or down
Several things move the total: the length of the loan, the interest rate on it, whether the contract is paid up front or financed, and how much of the contract is folded into the amount you borrow. A shorter loan usually reduces the interest the contract adds. Paying part of the contract in cash reduces the amount that accrues interest. These are general effects, and the exact result depends on your lender's terms. Use the lender's disclosure to work out the numbers, not an estimate from the seller.
When financing makes sense
Financing can suit a buyer who needs to keep cash on hand for repairs or other bills. It can also suit someone who wants the contract payments to line up with the loan schedule. It works against a buyer who will pay off the loan early anyway and would have paid the contract in cash, because the interest then buys nothing. Be honest about which buyer you are before the finance desk makes the choice for you.
What this does not show
This article describes how financing generally works, not what any particular company's contract or lender charges. Our tables list published terms for the companies we cover, and the contract you are offered is the document that controls.