Cinder blocks instead of wood raised beds. Plus you could plant herbs or strawberries *in* the cinder blocks themselves!
gutter herb garden
Stones around raised garden beds. Love this idea for a vegetable garden.
Lay down a thick layer of CARDBOARD in your raised garden beds to kill the grass. It is perfectly safe to use and will fully decompose, but not before killing any grass below it. They’ll also provide compost and food for worms. @ Home Improvement Ideas
Building lasagna raised bed garden. Love this idea - http://archers-at-the-larches.blogspot.co.uk/