There are times when you would like your client to select a certain amount of the product you're selling; whether it's time allotment, or a certain number of an item. Here's how to set an optional quantity for your fee table.
(Note: This will only work for rows that are not Fixed-style.)
First, click into the row you would like to make editable. Then, look for the "Row Settings" segment under the "Copy To Fee Library" button in the right-hand menu:
From there, check the box next to "Editable Quantity":
This will allow your client to choose exactly how much of a particular product to sign up for, and this total will automatically be calculated and added to the total: