I'm not smart enough to figure anything like this out myself the first time I try it so I bought the $6 .pdf file from these people:
Take a closer look: Weekend Workbench Plan
I've built this bench twice. It's sturdy, cheap, and easy to complete. I followed the plans and used a solid core door the first time. The 2nd time, I had a smaller footprint to work in and was in the middle of a kitchen remodel, so I scaled it down a little and used my old kitchen countertop for the top.