Need some input about pricing. there are a few small guy used car lots in my area and i want to offer them a package deal for cleaning there cars on the lot after rain,pollen get them dirty again. i'm thinking of using poorbys spray and wipe or a similar product. since i am not mobile it would have to be a waterless product. i have already talked to them about a detail when they first get the car but would like to have a chance to keep them clean for them.the number of cars they have on average is around 12- 20. any advice would be a big help. Thanks Scott