The OEM replacement pads aren't too spendy, but they do add up if you replace them all (front and rear, inner and outer pads).
You don't have to remove the glass to get to them. IIRC you just unbolt the brackets holding the two inner ones on and then the window can be pulled slightly inward to access the outers (with the window down of course). I was able to remove the outers by prying on them with a flat blade screw driver. They clip into the sheet metal, but also have adhesive on the back side that hold them in place.
It's a pretty easy job, I've done all of mine. Unfortunately it was too late for my front driver's side window.
