I'm so happy to give you these plans today. I know they have been requested many times over, and I just couldn't quite figure out how to build these without tons of leftover wood or having to create panels for the shelf bottoms. I think I've done it, made it a plan I am proud to put my name on. But there's no way around it, you are going to need a full sheet of plywood to build one . . . or two.
And while this plan only calls for one leaning wall shelf, you will have enough scrap plywood or MDF leftover to build a second one.
Other ways that you can save? 2x4s are cheaper than 1x4s, so try adding strength and saving several dollars by using 2x4s for the legs. 1x3s are about 1/2 the cost of 1x4s, so try using 1x3s for the shelf trim instead of the 1x4 shelf trim.