Each week Pathmark has two web-coupons for one cent items. One is for a Pathmark-brand item and the other is for a name-brand item. There are links to the two coupons on the main page
http://www.pathmark.com/
The Advantage Club card is the Pathmark "loyalty" card you sign up for at the store. It is no-cost. You need it to take advantage of most of the weekly specials and to get double coupons when offered.
Also, in the NYC metro area, A&P also has a $5 off $75 web-coupon at
http://www.apmetro.com/5coup.htm. Not alot, but decent for big families that shop there anyway.