Owning a car in cold country means budgeting for hidden costs that go well past fuel and routine maintenance. A dedicated set of studless snow tires runs about $850, but trying to stretch worn all-seasons over frozen slush usually ends with a ditch and an expensive tow bill. The softest pricing window is early October, right before the winter tire rush hits and shops clean out inventory.
Always separate buying the rubber from how you pay for it. You haggle the package price and shop fees first, then lean on a financing window to handle the cost as an equipment upgrade rather than an emergency cash drain.
Remember that the 18-month window is an absolute deadline, not free money. If you still carry a balance after month 18, the card's standard ongoing variable APR applies to the remaining balance immediately.