A while back, it was posted that PG stuff is avail at Wal-Mart. I looked, and my local Wal-Mart did Not have any PG, save for RV antifreeze for potable water lines. It said specifically NOT to use it in gasoline or diesel engines. So, Autozone had the Prestone Low-Tox for $7/Gal UNdiluted. Just FYI
KMart has Siera(not sure if that is how it's spelled) which is PG. You may want to check that out.