Smart video doorbells are built to keep package thieves honest and let you see who is outside without getting off the couch. A decent setup should easily last you four to five years, so do not overpay for minor yearly spec bumps. Most brands refresh their hardware every fall, which means last year's model usually does the exact same core job at a steep discount.
Expect to spend around $200 for a quality doorbell bundled with an indoor chime unit. If you plan your purchase right and split up the payments without interest, it barely dents your monthly cash flow.
A 0% intro rate is a firm deadline, not free money. If you still have a balance when the 15-month window ends, standard interest kicks in on whatever is left, so set your monthly payments to finish the job ahead of time.