For example, I swapped from one brand to another, and thus wanted some people to test the new brand; how it applied, how well it lasted etc I offered my customers 20% off their appt. I've also offered 20-25% off for testing out new techniques, etc. Loads were interested with 20% off, even if they didn't have much "choice" in shape/colour. So I think in such a scenario, don't do them for free. If you have a clientele already, then try to offer a discount. But if you don't have any customers, you could start off lower just to get the practice in + enhance your portfolio as you say. If it was your first ever set of nails or if it's for an exam of sorts, then don't charge. But otherwise, do charge some money, even if just to cover your costs.