To Design a flag is not a very difficult task. In fact, you could probably get children to draw flag shapes on colored paper and cut them out or you could go all out and get one sewn out of nylon and polyester. Flags can be made as a Golf flag pennants or any other more traditional types and you do not have to visit a flag maker to get it done.
When creating your flag use a design that is simple and is in single or double colour schemes. It should also be something that could be recognized as well as something easy to draw. You will have to refrain from complex designs as the flags will be fabric and hanging most of the time or flown and cannot show off their elaborate designs.