Purchase 8″ (for a 2″ or less outside diameter pole) plastic cable ties at you local hardware store. You’ll need only four of them. Lay one tie parallel to the pole at each of the two metal grommet holes in your flag. Wrap another tie over these and lock it tightly around the pole. The parallel ties are then inserted in the flag’s grommet holes and tightened when needed. Note longer cables will be needed with larger than 2″ diameter poles.
Re: Another low cost idea! MtnMagic