I'm just getting started in reloading and had no bench. I'm also severely $$ & space limited. My first attempt was a Harbor Freight vice table with a piece of 3/4" plywood on a piece of 2x4. Too light, too wobbly. My son in law had a big speaker box he was tossing out. The more I looked at it the more I saw possibilities. I still plan on adding a removable shelf and a box to hold my powder scale. I added some 2x6 scraps for feet with plastic sliding chair protectors so I don't mess up the floor. I added my board with my two presses on it. My big boxes with reloading stuff will go below it for extra weight.
Here's what I made.