There are a couple of reasons why you might have been charged a fee for your client's order.
Cost of good sold for products
For all automatic fulfillment orders, the cost of prints and shipping are collected at the time the order is placed, and forwarded to the print lab directly. Normally, this is deducted directly from the client's payment. However, if there is not enough money to cover the cost, the difference will be charged to your credit card on file.
For example, if your client used a coupon to bring the total transaction down to any amount that is less than the total cost of goods sold, we will charge your payment profile on file for any unpaid cost of goods sold.
Learn more: What is cost of goods sold / application fee?
You are using the Free account
All orders received while you are using the Free account are subject to 15% commission fee. This fee is charged on the subtotal before shipping, taxes, or discounts are applied. If you are providing your client used a coupon that brought the total to zero, you will still be charged the commission fee because the fee is calculated based on the subtotal before discounts are applied.
There are no commission fees charged on any of the upgraded accounts. If selling is a major part of your workflow, we recommend upgrading to avoid this fee. Our plans start as low as $8 a month. You can see our pricing here.