Lowe's, Home Depot, and most hardware and plumbing stores sell faucet replacement cartridges. Replacing these cartridges helps to stop leaking faucets. As of 2015, the kits range in price from under $10 to over $50.
Cartridge type faucets help to reduce the number of dripping fixtures in the home. These faucets use a cartridge to stop the water flow instead of a rubber washer. While the cartridges last longer than the washer, they eventually wear and require replacement. In most cases, consumers find it less expensive to replace the cartridge than the entire dripping faucet.
Before replacing the cartridge for a faucet that leaks from the tap, The Family Handyman recommends replacing the seat and spring, which cost less than the cartridge. If the faucet continues to drip from the spout, the cartridge is the next replacement to make. Handle leaks indicate it is time to replace both the o-ring and the cartridge to prevent further leaks.
Cartridges vary and the best approach is shutting off the water and removing the cartridge before purchasing a replacement. This allows taking the current cartridge to the store to ensure an exact replacement. However, some manufacturers offer online assistance for determining the part number the fixture requires for replacement.