A dash cam is one of those things you hope to never use but are incredibly glad to have when a bad driver hits your fender. It records exactly what happens, which can save you a mountain of stress and insurance headaches. Expect to pay about $300 for a solid setup that covers both the front and rear of your vehicle.
Timing is everything here. Retailers usually run deep clearance sales right after the holidays to clear out inventory. If you wait until the end of the year to buy, you can often grab the high-end gear at a mid-range price.
Remember that the 18-month intro window is a deadline, not free money. If you have any balance remaining once those 18 months are up, you will start paying interest on whatever is left over.