cost to replace a serpentine belt

Definitely change your belt. On your car the ac compressor has to be partially removed to replace it. I would have them inspect your water pump power steering pump and the rest of your pulleys while they are working on it and do not hesitate to replace them if they are questionable. Lastly I would recommend oe parts or better to avoid any potential failures caused by cheaper made aftermarket parts. Replacement of the belt itself is about a 3 hour job with about $50 in parts. Other parts would increase these numbers. Most shops charge $100-$150 per hour.