From JiffyLube.com:

As the busy summer driving season approaches, Jiffy Lube® and Pennzoil® are giving drivers an easier way to make an important change - to their motor oil. Between April 29 and June 4, 2007, drivers who visit any participating Jiffy Lube® service center and purchase a Jiffy Lube Signature Service® Oil Change with any conventional, specialty or synthetic Pennzoil® or Quaker State® product can get the next one free (equal or lesser value).

Through June 4th, customers who take advantage of this buy-one-get-one-free promotion will receive a mail-in form for a coupon that is redeemable through the end of September 2007.

Frederick Jiffy Lube
1210 West Patrick Street.
Phone: (301) 663-6666.