What an interesting topic! I love the business aspect of it. Sounds like NYX is a good choice for the salon you work at. For a different clientele selling a brand that is exclusively sold in spas and salons (high quality, higher end, completely natural or organic products, a brand that also sells non-cosmetic products) could be the way to go. I know that this is the type of products that has the most potential at getting me to spend my money, especially over a period of time. In fact, there's a salon I go to all the time to buy my moisturizer and a powder I like, occaisionally I get the cleanser or face mask... They probably make 15-20$ profit per product I buy from them! They do facials at this salon though so this brand they sell makes sense for that reason, and the focus is less on cosmetics, though they have some. For one-time event makeup like you do, it sounds like a less expensive brand is the way to go though.