How to create a generic service item in coreSTORE

Start by creating an item, you can name it whatever you want. Scroll down and make sure the "Is service" box is checked. 

Now, just type the item into the sales screen and set the fee to what you want it to be for that sale. If you want a flat fee for all shipping, that can also be set when originally creating the item. 

An additional step you could do instead of typing in the item name into the sale is to set it up on the grid. To do this, all you need to do is set the category to show on the grid:

This Category is now visible on the grid and has a button that can be pressed to add this item to the sale.