The conditions of a permissible Murabahah include: 1- The customer tells the company about the products they want to acquire. 2- The company buys these products for itself. 3- The company takes possession of the products and moves them from the dealer’s place. 4- The company sells the products to the customer after taking possession of them. 5- Once the company has sold the products to you, it is permissible for you to use them to build the house or to sell them.

There is nothing wrong with you designing a drawing or writing to be put on a T-shirt, so that if the T-shirt is sold via Amazon, you will get a share of its price, and if it is not sold you will not get anything.