There are a couple of reasons why you might have been charged a fee for your client's order.
Cost of goods sold
For all automatic fulfillment orders, the cost of goods sold (cost for printing the products) and shipping are collected when the order is placed, and forwarded to the print lab directly.
Learn more: What is cost of goods sold / application fee?
Note that: if there is not enough funds in the transaction to cover the cost (e.g. coupons used), the difference will be charged to your credit card on file.
Commission on 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.