Saltwater, sand, and wet board shorts are brutal on factory upholstery. Keeping your car clean after a weekend at the coast takes real work, and replacing ruined factory seats costs way more than a set of custom-fit neoprene covers. If you are ordering a set right before beach season hits, the price tends to hold firm since everyone else has the exact same idea.
Timing matters more than the brand you choose. Look for holiday sales around Memorial Day or late summer markdowns when shops want to clear shelf space. Once you lock in the best price on the covers themselves, you can figure out how to split up the payments without getting slammed by interest.
Remember that the 0% intro APR window is a hard deadline, not free money. If you still have a balance left on the covers when those 15 months run out, deferred interest will hit the remaining amount hard.