A good set of all-terrain tires changes how your car handles dirt and rain, but they are a hefty lump sum to drop all at once. If you maintain your vehicle properly, you can usually spot tread wear coming months in advance, giving you time to plan for the expense rather than reacting to a flat.
Look for manufacturer rebates during holiday weekends or seasonal changeovers, when tire brands push for volume. Getting a few hundred dollars back by mail is standard, but you should treat that as a bonus rather than your primary savings.
Remember that the 0% intro APR is a deadline, not free money. If you have any balance left after 15 months, the interest kicks in on the remaining amount at the standard rate.