Have just noticed that someone on Adverts.ie is offering "blown down" fencing free ... it's likely to be pressure-treated, so would have quite a decent amount of life left in it. Here is the link:
http://www.adverts.ie/showproduct.ph...=146973&cat=42
You could also try:
http://www.dublinwaste.ie/free_trade.php
There are usually quite a few doors on offer ... a bit of DIY could turn a couple of old doors into quite a respectable raised bed !
Another thought ... every so often free pallets are available -- either from online forums or from builder suppliers yards. Back to DIY, again, but it's amazing what can be done with a couple of pallets.
Regards, Anonany