Well I have gotten a lot of help from this forum so time for me to pass along...
I use Floral Wire (4 bucks at Walmart in the craft section)
You need
Floral Wire
Snips
Plastic cup
Needlenose Pliers
Start by pulling a length of wire off the spool then bend so you get two lengths 60
cm will give you 30cm of wire - etc.
Then with the pliers grab and end and work down the length and twist closely but loosely
Start by cutting a bunch of lengths of short wire about 2cm long (i uses just over my thumb width) into a plastic Cup
they will fly all over if you don't
Bend all the wires into an arched half
Insert one end of the bent bit in between the wires (if you dont they barbs will slide all over the length of wire) one at a time
Wrap the bit around
Then pinch them close with the needle noses DO ONE
AT A TIME - if you don't you will find yourself stabbing your fingers
with the wire
Rinse and repeat
Twist - pinch etc etc until you get to the end and BLAMMO crap loads of barbed wire for dirt cheap