We mainly recommend purchasing our 18"x12" with of our pre-designed templates available at www.quickyardsigns.com
and placing the largest quantity possible over a certain area, as constantly seeing the same sign over and over will attract the most customers even if it has a smaller size. (this instead of investing in one big banner)
We also have the 24" x 9" (horizontal shape) which is very popular.
Both of these are available 100 for $100.00, pretty cheap.
Our signs are made of durable 4mm coroplast.
Keep the questions coming.