I've decided to try out the duragloss enviroshield coating. It comes with the coating and a prep polish. I've been told that I can get more than one application out of this bottle. My question is that it comes with what seems to be a small bottle of the prep polish and AG doesn't seem to sell the duragloss prep polish separate so what could I use instead? I want to make an order before the sale ends. I'm new to detailing and coatings so I image I will end up wasting a lot thats why I'm wondering. I also live in Hawaii and the shipping is higher to here so I would like to just make one order.