Most restaurants do not make beer, wine or soda, yet sell at significant mark-ups. The same with candy, chips and other items. I think 3x markup is a reasonable thing. And, as was previously stated, you still have risk in that you may not sell the item before it becomes unsaleable. And ice cream cones is a great example, you definitely have waste everytime you open a bag, unless you sell out. There is nothing worse than a stale cone.
I'm feeling bearish, and I'm packing a Wusthof Grand Brisket slicer from MABA
"perhaps...but then again...maybe not..."