Building a big table?

If you really want to go cheap! Then look around for some wood pallets. You may be able to use the runners for legs and connect the others with the slats. Top it off with some underlay. The thin plywood they use for flooring under vinyl flooring. Drive around the industrial area where you live to find pallet and always ask for permission to take them and get the name of the person that says you can have them first.