I have done several of these banners for groups that get permits from the city to hang them over the main street across town. As the City has changed their requirements the price has gone up and at this point I thought I'd check and see what others that do vinyl banners would charge.
The banner would be 5'H x 25'W, 14 oz vinyl, reinforced corners, windslits, and pockets sewn in top and bottom (double-stitched) with 1/4" airline cable inserted, loops on each end of the cables for mounting. Lettering is 1 line of 30" vinyl lettering, one line of 6" lettering in another color, one line of 12" lettering in a 3rd color, on both sides.
Here is a mockup of the latest one I just quoted (edit - for some reason it scrunched up when I uploaded,it's really 5 times as wide as high.)
Update: I quoted $2,280, that's materials, labor, overhead and 50% profit, the least I would do it for considering the PIA factor.