Let's say you've got 10,000 FT of sidewalls for a tent and you want to be able to add and charge the sidewall by foot.

First up, when creating your item, name it by the item name and the measurement you'd like to track and charge by. For example, I'd want to charge my clients per foot, so I named the item Cathedral Sidewalls 1 Ft.

Then, I'd add how many feet I have in stock for this item. For example, I know I have 10,000 FT in stock.

Finally, I'd add the price I want to charge per day and per foot. In this example, I'd charge my clients 2.00/day/foot.