I am probably reacting too quickly, but I note about 3 other places (not including the sibling comment to this one) where people have asked you whether or not you charge a markup and purchases, and you've not answered.
Granted, it's only been an hour, but that silence doesn't make me feel good.
Nope, at this point, we don't take any percentage or fee. We even pass along any discounts we receive (we get up to 15% off flower some purchases for example and we pass that along to you).