Creating a homemade banner

The cheapest is a stiff cotton (off a full size fabric bolt, you can often get remnants at a fabric store that are large enough) and waterfast (repeat after me waterfast, waterfast, waterfast) fabric paint (available at most craft stores). Use a computer to design and print out your design/logo and wording onto a clear acetate (plastic sheet the size of a sheet of paper -- all the office supply stores carry them, you have to ask sometimes though, they are often stored in the oddest places) - this is almost always better than trying to freehand it. Borrow an old overhead projector (often churches or school will have them and are often very good about lending them out to someone they know). Tape fabric to the wall (probably folded over and a single seam sewn along the top (do the bottom seam AFTER), project your logo/image/what have you onto the fabric, use a dark, soft pencil and trace the outlines of the logo/letters - when done, remove the fabric from the wall and lay out flat on a table or the floor - one thickness of cloth only. Using the WATERFAST fabric paint -- paint between the lines you traced. When it is dry, close the bottom seam (if you do it before, paint my seep through... you can also paint both sides, although depending on how thick your fabric is, the image may seem to "bleed" through). Slightly more expensive is to purchase a white or tan tarpaulin or plastic drop cloth and do the same thing (overhead projection and paint) although you might have to do the outline with a thin marker rather than a pencil, and will use oil-based model paints instead of fabric paint. While sturdier, there is a tendency for the paint to crack and flake since it is riding on the surface of the tarp rather than being partially absorbed into the fabric. For both variations, rather than messing with grommets and crap like that, fold back the ends of the banner and sew them into a "pocket" wide enough to support your carrying poles (the least expensive and lightest poles are the oversized bamboo gardening poles (3/4 to 1 inch in diameter) carried in gardening supply stores. You are the judge of local weather (you might be in Lethbridge for example), you might want to make crescent shaped slits along the banner to reduce the drag strong winds create, there is always the risk such cuts will "spread".

[ETA... when I said cotton, I meant cotton... some of the artificial fabrics will not really hold onto the fabric paint... the stuff used for backing heavy curtains is ideal]

WOW ! That really thourough ! Have you ever tried sewing on letter cut out- does that go well ?

Never tried, as I don't actually know how to sew (but fortunately someone else in the group had access to a sewing machine, so could do the necessary seams) The banner that I learned to do this for was the provincial Alberta NDP, the old 1990s logo (the letters ND made up of horizontal lines of differing thicknesses, actually kind of complicated) and maybe people just avoided saying so in my presence, but I heard no complaints about the quality of the finished product {complaints were reserved for the then current slogan which we had incorporated on the banner). Managed to make 2 banners (about 8 feet wide, 3 high) for approximately $35 for all supplies. A couple of years later we priced having one made with the federal party logo, cheapest we could find (silk screen on plastic tarp material with grommets) was about $180. -- An observation from having done this... the banner had a lof of lettering, part in a serif font, part in san serif... although it took a bit of effort, the serif font really stood out better (I believe it was Palatino or a variant thereo).

coffee shops that roast/import their own coffee sometimes have heavy coffee bags that can be sewn into banners. they usually give them away if you ask

Tubes of speed sew are faster. fabricate letters from ripped widths selviged/hemned to width with speed sew. attach to banner w/ speed sew- carefully put under mattresss to press flat and set glue.

Not sure how big this is going to be but you can buy vinyl lettering that you could just steam on to sturdy fabric.  Would be waterproof and eyecatching.  Is this related to the Olympics?