Last year, there was a guy at the Texas Pinball Festival, selling glass for normal size machines for $25, cash and carry.
As far as I know, there was nothing special about the glass.
I got one sheet and it fits perfectly with smooth edges.
Looks very clean with no scratches or imperfections that I can see.
At that price, I got an extra one, just in case...
Shipping costs on glass is expensive.