When it comes to tunnel washes, "price" is usually calculated on a blended cost/car average. This can vary widely depending on the tunnel setup, chemical delivery systems, wash package offerings and operator preferences. If you're shopping chemicals, I would focus more on the "who." A good chemical rep/company will work with you to get the cleanest, shiniest, driest car you can get with in your budget and quite frankly, show you how you can make more money with your offerings. In addition, they will provide the technical support and hands on support that you need to put out the best product to your customer.