Hiya,
We bought a roll of stuff similar to this, and some metal posts from Ebay very cheaply:
I'm afraid it's pretty rubbish though.
It would be ok if stapled to a rigid frame for instance, but used with the posts it has a tendency to 'concertina' and form wobbles at the bottom. The birds (particularly ducks) stick their heads out underneath, and before you know it, they're running around outside and wondering how to get back in!