Art retailer's dilemma

I talked to my friend George about the problems with beginners' supplies yesterday, and as I suspected, it was a combination of sticker shock and inexperience. The students did, indeed, present my list, then said they wanted the cheapest materials to fulfill the requirements. Most of the employees there know I hold high standards for supplies, but newer ones made some unacceptable substitutions. Poster paints won't do for a transparent watercolor class! I will definitely have the next class come without supplies so I can indoctrinate them before they go out to buy their materials. Maybe I should work up a chart showing the differences in quality of brushes, papers and paints to make it more convincing. I used to have McCallister's make up kits for me and the students didn't bat an eye at spending $50-60 for it, but it was a problem getting the kits together because I never know how many students I'll have until the first day. Some classes are very small, like this one (10) and some are up to 25. Can't seem to work out the logistics. Anyway, there has to be a better way to do this. Any ideas out there?