Selling graphic T-shirts is big business. Customized T-shirts with clever sayings or graphics are ideal for online sales. Sites like Teespring allow you to sell customer shirts. Teespring’s unique model allows you to design the shirt and get buyers lined up to purchase it. This saves you from the initial investment in stock and the time on processing and shipping orders, though you’ll likely make a smaller profit on each shirt sold.
Analytics are limited. Unlike with conversions made directly on your WordPress site, you’ll be limited in terms of what you can learn about the people making purchases through your affiliate links. While Amazon does provide you with details about clicks and sales, you won’t get deep insights into who the consumer was and what they did on your site before they got to that point that you would with Google Analytics.