A good dual-camera dash cam gives you peace of mind, recording the road ahead and behind just in case someone does something stupid in traffic. Hardwiring the kit means it runs cleanly without dangling cords and keeps recording while you are parked, but paying $350 upfront for the gear and installation bits can sting. The trick is waiting for major online shopping events when prices drop, since that is when you will get the best deal on the camera itself.
You should negotiate the price of the hardware and the installation parts separately before you even think about how to pay. Once you have the final bottom line, you can decide how to handle the cash flow without draining your emergency fund on a piece of electronics.
Remember that the 0% intro window is a strict deadline, not free money, and any remaining balance left over when the 18 months are up will suddenly start accruing standard interest.