Well, just a little bit of googling will give you this
http://www.ebay.co.uk/itm/Enviromesh-Bulk-rolls-Various-sizes-/321158432323?lgeo=1&clk_rvr_id=502603797616&vectorid=229508.. that's less than the £2 a metre I quoted and that took me a minute. And that's before any of us think on our feet. We all go on about free nitrogen from legumes etc rather than paying out at the garden centre, brilliantly effective cheap green manures that easily outperform many off the shelf fertilisers. Then the same applies to any garden product, provided the desire to do so is there... get asking for overspends at your local farm, club together, whatever. I personally buy it off my communal allotment association, about £1.90 per metre for the 2.1m width. There ws a demand, we got off our backsides and sourced it.
I did say my solution was to grow "dwarf" pea varieties, and hence a 2.1m width right over the row. A tasty pea is a tasty pea. I used to think French beans should only be grown up huge beanpoles. I don't anymore having tasted and grown fantastic dwarf versions. I am currently trialling a dwarf borlotti. Can't quite bring myself to growing dwarf runners if they exist. Some things are sacrosanct.
In the end, if we club together we get real prices, and in the end, if we have the desire, we will resource it. The trouble is it's too easy for an individual to rely on a chemical fix that's in your face 24/7, and that is how the agri/chemi industry has shaped itself.
If you want enviromesh at a proper price it's out there.