The best investment I ever made was a SewEzi portable sewing table. It allows my machine to be at the proper height for my arms and wrists and I can sew for hours without strain. It has interchangeable inserts for different machines and is slick so material slides across it. I can set it up anywhere and it fits in my car for taking to retreats. I waited until i could test it out at a show and it was sent to me in a very study shipping carton. I love it.
Before i used a office supply store table that did not have adjustable legs. The machine was 2-3 inches too high and it was uncomfortable to sew with only the extension table. Doable and I did use it for years and it only cost less than $40 new. Now it is my cutting table and the extension table for the Sewezi.