What do oil changes, haircuts, massages, and appointments have in common? None of these have a set number on the shelf. But we still want to be able to sell them!
Marking these kinds of non-inventory items is easy: Just turn off inventory tracking for those Variants in the Edit Item Panel.
With "Track Inventory Quantities" disabled, quantities will not be endlessly deducted (sending you into the negatives). This way, products still appear in the point of sale and on your Sales Reports, but don't have a meaningless number beside them.
Be sure to set your default cost for these Items before they sell, as costs are not able to be added to your sales reports later on.
Please let us know if you have any questions. We are here to help!