Cardboard concrete form tubes are light, strong, and relatively inexpensive. Flat-Forms offer the same advantages, but they also store flat—taking up less space for storage and transport. After opening up the form, the installer inserts a center support and places the form in a footing hole. A forming collar that slides over the top of the form helps stabilize it when the concrete is placed, and slits in the bottom allow the form to flare out when filled. Made in the U.S., the octagonal forms are 12 inches wide and 48 inches tall. Prices start at $14 each, not including shipping, but drop to $12 each for 10 or more. Flat-Forms, 651.460.3399, flat-forms.com