I just saw that Napa auto parts Online has this for sale @ 10% off when you reserve it online and pick up in the store. My local store is at: 1225 St George Avenue Colonia, NJ 07067, you should be able to pick up a 1L can for under $20.
Reserve from this link and just got pick it up (They close at 3pm today):
http://www.napaonline.com/Catalog/Ca...11S_0291109971