A smart thermostat keeps your house at the right temperature and trims your heating and cooling bills, so you want one that lasts for years rather than a cheap model you have to replace next season. New versions drop every fall, which means you can usually grab last year's proven model at a discount right before the winter rush.
We can make the math easier on this about $250 purchase by spreading out the cost, as long as we keep an eye on the calendar. Here is the straightforward way to get it done.
Remember that the 18 months on purchases and balance transfers from date of account opening is a hard deadline and not free money, so if you still have a balance left when it ends, you will get hit with standard interest on the original amount.