A kitchen sink that does not drain properly changes your daily routine fast. Replacing a disposal is usually a two-hour job for a pro, and hardware stores tend to run their best deals over holiday weekends when they push home improvement bundles.
Get at least three quotes from local handymen or plumbers before you buy the unit. Getting multiple bids keeps the labor costs honest, as some pros charge a flat fee while others bill by the hour.
Remember that the 18 months is a deadline, not a gift. If you have any balance left after the 18-month intro window ends, the standard interest rate will apply to what you still owe.