I use a number of different pads, for different purposes, all on the same typing surface (a smooth wood laminate desk):
* For relatively quiet and light-weight machines I use a square sheet of rubberized shelving material that prevents any typewriter from moving around.
​* For big standards (which typically don't have movement issues) I use a one inch thick felt pad to minimize vibration through the desk and reduce sound.
​* For any machine that I've recently repaired or serviced - or new-to-me machines that I'm testing out - I have an oversized, 10 mm thick, smooth rubber mat that not only prevents a machine from moving on the desk, but is also easy to clean (it collects the dirt that falls out of newly purchased machines, and also errant oil drips from recently serviced ones).

Update:  I bought a roll of Con-Tact brand kitchen drawer liner (kittrich.com).  Its a rubberized padded roll that goes in the bottom of a kitchen drawer to reduce the clanking and sliding of the kitchen utinsels.
The 1-1/2 foot x 10 foot roll cost me $5.99 from TJ Maxx.
I only needed an 11 inch x 12 inch piece for a typewriter pad, and a pair of scissors cuts through it quite easily.
Its grippy, and my typewriter doesn't slide around anymore on wood, glass, marble, or Formica. 
I didn't do any decibel reduction studies, so any change in noise is purely subjective at this point, but for five bucks, I have accomplished  my mission to keep the typewriter immobilized on my desk as I type.

There are two overlapping requirements in this thread, which is whether you need an anti-skid mat or one for sound deadening (or both). The rubberized shelf liner material is great for anti-skid, but does nothing for sound deadening. Some sound deadening materials are not always the best for keeping a typewriter in place. I like the idea of the yoga mat material because it has the potential to do both, and you could always double up the cut pieces to make a thicker pad.

​As for the one inch thick felt, you might have luck at a local building supply centre. If not, it is readily available online: http://www.thefeltstore.com/default.aspx?CN=811121B56AEC

I bought one of those replica vintage pads that mytypewriter.com was selling, and that thing is amazing. It's lasted a very long time and has served well for a lot of work. I have written a book over it and a ton of other stuff. 

My typewriters that get used on it are all big prewar standards and if it can help keep those from marring tables & desks, so much the better. Something has to quell the jolting and vibration from my old Remington.