You want a machine that prints parts for years, not weeks. Look for kits with open-source parts so you can swap out nozzles or motors when they wear out instead of tossing the whole printer.
Tech brands often drop new models in the spring, which makes late autumn the perfect time to find last year's proven hardware at a steep discount. A reliable older model is almost always a better deal than a buggy, full-priced new release.
The 0% intro APR is a deadline, not a gift. If you still have a balance after the 15 months are up, you will start paying interest on whatever remains.