I was limited in space and money to invest at that time so I built my setup around my desk and office-chair (Racing-style seat / DX-Racer).
I already had purchased a good used set of pedals with a load-cell brake and needed far more holding power for the seat if I was going to be able to take full advantage of the pedal setup. I knew I would eventually want to build a versatile but solid race-rig however, I needed to do it in stages over time.
I could have choses to use wood but, I used aluminum profile (as in 80/20 type / 350mm square) to mount the pedals to and extending under the seat. The chair-pedestal wheels fit in and around the profile locking it in place. This allowed me to crank up the load-cell so that I could apply much more brake force.
Another plus to this approach was that I could add a mount for both the shifter and hand-brake that I wanted to include. I used basic rubber feet under the profile for excellent holding power on the office floor. I now had a solid foundation on which I could expand on.
This simple framework formed the base design of what would eventually, incorporate a multi-faceted tactile setup and ultimately, a motion-rig; so virtually all of the aluminum profile used in the original frame is still being used today in one way or another.
I just put a square of thick "puffy" cardboard under my chair when I race. Easy to remove, costs next to nothing. You just have to replace the cardboard once in a while as it gets slowly squashed over time and the wheels start to roll on it again.