To start, cattle panel is approximately 4 feet wide and 16 feet long. It is made of galvanized, heavy gauge wire - much sturdier than your average garden fencing. It's galvanized so it won't rust like concrete reinforcing wire.
It's not typically sold at Home Depot, but here in the Raleigh area, it's sold at both Tractor Supply and Agri-supply for between $20 and $25.
As for the uses, well, obviously, it's suitable for use as a arched trellis - I've already done this in my yard:
|Cattle Panel Arch Trellis in my garden.|
Of course, it would make an excellent vertical trellis for just about any vegetable, but especially so if you're growing heavier fruits vertically, like canteloupe and those sugar baby watermelons. If my wife would let me, I'd put in a 2'x16' bed and use this as a cucumber trellis.
|Cucumber Trellises made from Cattle Panel|
But what I hadn't considered were its uses as building material. For example, check out Eric's Projects: Greenhouse made from 2x4s and Cattle Panel:
|Greenhouse made from Cattle Panel|
This makes me wish I had a bigger yard, I want a cheap, low cost greenhouse too! Eric also built a chicken coop out of Cattle Panel.