[protoserge]

Iron-on transfers work great. I think we just used a piece of trimmed fabric from the fabric supply store and affixed it to a pole.

You might be able to find a parent or mentor who is willing to sew your logo and team name (assuming it's simple enough to be cut) to a flag-sized piece.

I believe JCPenny has given teams [generic] flags in the past as part of their sponsorship.