The Toyota Prius battery cost is more expensive to replace than the engine itself. Typical battery costs are around $4,000. However, lower cost batteries can be found, but they are not OEM (original equipment manufacturer) products. A non-OEM battery may cost less, but you run the risk of it not performing or lasting as long as the OEM version. The Prius battery, like other rechargeable batteries, can be rebuilt. A rebuild is significantly cheaper. But, if quality materials are not used, or if all of the materials are not replaced, you could end up with a battery that is unable to handle the demands put upon it.