A suspension overhaul is one of those repairs that hurts to pay for but makes the car feel brand new. When your struts and shocks go, the handling gets loose and every bump in the road feels like a direct hit to the chassis.
You are looking at about $600 for a quality kit. Watch for big holiday sales at major auto parts warehouses to catch the best price, and always verify the part numbers against your specific car model before you pull the trigger.
The 0% intro APR is a tool for managing cash flow, not a discount on the parts themselves. If you haven't paid off the full $600 by the time the 15 months are up, the bank will start charging interest on whatever balance remains.