Milk Crates

Description Highly durable, light plastic containers that may be repurposed for a number of uses; easily movable and stackable (though not collapsible!).
Typical Dimensions 13 in. long x 13 in. wide x 11 in. high (Square); or 18.75 in. long x 13 in. wide x 11 in. high (rectangular). 
Estimated Cost Can often be reclaimed from waste stream or received via donation. $4.75 (square) or $8.00 (rectangular) / unit.
Durability Demo: 1 day to 1 month installation / Pilot: 1 month to 1 year installation

All Projects Milke crates may be used as barrier elements or planters, and used just like the wooden planters also described in this guide.
Curb Extensions / Plazas / Activated Alleys Milk crates are durable enough to sit on and cost less than foldable chairs.

Consider aesthetics, as milk crates may not be ideal for all projects - though colorful crates can be used to make certain projects "pop!"
Note that while crates easily stack, they do not nest or fold, meaning storage and transport can be challenging if space is limited.

Can often be reclaimed from waste stream or received via donation.
Transport supply retailer, such as www.milkcratesdirect.com or www.uline.com