You can control the margin of your products when you sync your products from the SwagUp App. If you want to edit the margin, you can adjust in the Shopify app under products. You will see the cost saved in your products once they are synced.
When you sync products you can adjust margins as you add products from the SwagUp App to Shopify.
If you already have products synced you can always adjust the price on the products tab within Shopify.
For more questions on how to get started, you can email email@example.com