I use an interlocking system of mats around my main workbench that
definitely reduce the strain of working on a plain concrete floor. I found
them several years ago in a Sams Wholesale store at about $7.00 per package
of four. Each mat is approximately 2' x 2'. They even came with matching,
interlocking edge pieces to eliminate the jagged interlocking toothed edges.
The only problem was that each package contained one each of the four
primary colors of red, green, blue and yellow - a bit loud for my tastes.

Since then, I have seen similar packages of four mats, the same size, at
Home Depot. Only there they were over $20 per package. They were a nice,
neutral gray color, but for that much savings, I can squint. Once they get
a bit of wear on them, who cares?

Good luck.

Wade