Unless I'm mistaken 6-32 and 8-32 are two of THE most commonly used thread sizes for electrical work and are used in most of the outlets, lamp fixtures, and switches in any house in the US.
Believe me they have 8-32 screws in ANY hardware store, big or small.
If I had to guess I would say they rank right behind the venerable 1/4" 20 as the three most commonly used sizes in the US.

 

i will have to check the electrical dept.

 

If you look in the nuts and bolts (hardware dept.) sections of Home Depot or Lowes you'll find them hanging in little bags along with hundreds of other sizes.

Sometimes you have to look hard to find the exact size you want because of the sheer numbers of bags. But they are there if you look hard enough.

I 'think' (I can't swear to it) the Stainless steel ones are in orange bags in Home Depot. While Lowes has them in green bags for about a $1 a bag. Or the other way around, I'm sorry I can't remember which one is which right now.