Cheap sides for raised veggie beds

I use decking, but I only buy it when it's on offer, and with my aged parent in tow to add the OAP discount.

I use pressure treated fence boards - 6" wide and £1.20 for a 6ft length from my local timber yard. Admittedly they're not as thick as scaff, but the pressure treating means they'll last a good few years, and an that price I can afford to replace them for not too much cash when they do rot out