The flags will be cool. Very noticable and low cost, but time consuming and difficult to make. At least for me! I bet I could figure out the details and start selling them, but I don't have the time
Depends on how you want them printed? I can do the vinyl transfer (same stuff as the jerseys) on hats. And I might be getting into silk screening hats soon. It requires a special $300 adapter for my silk screen press but I may have a large enough order to justify buying it.