To use an icon in items for resale (such as tshirts, phone cases, stickers, mugs), you must purchase a license for each icon using the individual purchase feature and Pay $1.99. NounPro or NounTeam accounts may not be used to download icons for items for resale. One icon license purchased may be used for up to 100 units of product.
For example, if you're selling 500 tshirts with the same icon design, you will need to purchase 5 icon licenses (500 tshirts / 100 units per license).
If you're unsure if your items are considered Resale or Commercial use, please read here https://thenounproject.zendesk.com/hc/en-us/articles/200744393-What-s-the-difference-between-Commercial-Use-and-Items-for-Resale-