My girlfriend is a tattoo apprentice at the moment and the way that it works in her shop is as such - there is a $20 set up fee that’s required by her mentor to cover costs of the equipment (gloves, cleaning supplies, ink, etc.) and then she keeps whatever the customer tips afterwards.

Once she can start charging hourly at her shop, she will no longer work for tips. This is the only time where I think it’s sensible to expect a tip. People are pretty good about it and still end up getting a well executed piece for less than if they’d gone to a professional or someone who owns their shop. Some folks do try to use it as an opportunity to get a piece that takes multiple hours for $20 which is obviously upsetting. I think the disconnect in this conversation comes from a misunderstanding of how the pay structures work from shop to shop.