When I moved into our house, I had a small metal workbench that I brought with us. It is perfectly usable, but I finally had an opportunity to make an over-sized beast of a workbench where everything could be laid out and easily accessible.
While researching designs, I came across this video by Steve Ramsey. It shows a cheap, sturdy concept made out of 2x4's and plywood.
I was not aiming for something attractive, but utilitarian, cheap and fast to assemble.