A shop minimum on anything in your shop should be the norm. If you buy a burger at any fast food place.... you always do better when buying the meal package.
Whatever amount you set your price at... is entirely up to you, but when you think about it... if for one week, everyone that came in and ordered just little crap, you'd be complaining about all the little pint-sized orders. Why did I invest in this expensive machine ?? Where are the larger orders and so forth. So, prepare ahead of time for this and set your shop minumum to reflect those off times and you'll be surprised at how this small procedure enhances your bottom line.
No sense in giving stuff away. Smart people don't.......