Thee are 3 kinds of yard or lawn signs.
Poly bag signs are plastic bags that fit tightly over a metal frame. They are available only in very high volumes (more than 1,000).
The two other types are corrugated plastic and fold-over coated posterboard. The fold-over signs are sometimes cheaper, and the corrugated signs require a more expensive metal frame. The fold-over signs, being paper, may be the more environmentally friendly choice. The corrugated plastic is not opaque, so clear areas will show the design from the other side, especially with the sun behind it.
The corrugated signs are the most durable, but that may not be a concern with a contentious issue that will see many of the signs getting stolen. Many localities also limit how long such campaign signs can be displayed. Fold-over signs will last for several months.
The cost per sign goes down as the size of an order increases.
The cost goes up as more colors are needed. A shade of a color (e.g., 50% blue) is usually considered as a separate color. Most suppliers use a stock set of ink colors, some with more variety than others. It is therefore best to design with generic colors in mind – i.e., black, red, blue, green, etc. – and no shades of any color. White (no ink) letters in a colored background are a very effective use of a single color.
Fold-over signs are generally 22 × 14 inches.
Corrugated signs are generally 24 × 18 inches.
Poly bag signs are 26 × 16 inches.
The design can not bleed off the edge – the sizes include a half-inch unprinted border.
Ask the supplier for file instructions. Besides file format (e.g., EPS) the colors may need to be designated in a specific way (e.g., Pantone spot). There may be a setup fee for submitted files.