They are absolutely worth it! If you look around, food tours are usually between $35-$60 and not only you get a guided tour of the place you visit but for that price you also get to taste about 5-6 different types of food. A total bargain, food for thought =)
I appreciate the mention of my self-guided tour, snaporaz. Two updates: Guss' Pickles has closed, so substitute The Pickle Guys, on Essex St. And the correct address for Economy Candy is 108 Rivington St. (not 145).