I never bulk purchased. I started my program by buying a couple of boxes at the center, then buying a half-case of caramel crunch bars on ebay. A lot of people finish their programs and have bars left over---especially people who bulk purchased a ton of bars! I get amazing deals on the bars, as well as snacks, shakes and biscotti. If you are not afraid to be assertive, and can ask a lot of questions of the sellers (have these bars been sitting around your house for a long time, or are they fresh from the center?) you can shop with confidence.
My center had specials on the bars often enough so that I could have a nice supply in case I couldn't find what I wanted on ebay.
Another reason to buy online---you can try flavors they don't sell in your area. I love the chocolate caramel deluxe, as well as the fruit&oat---the latter was discontinued in my area about two years ago. I make sure I get the fruit&oat bars with the 2005 copyright date on them. The 2003 copyright bars are usually dry tasting. The newer flavors all have expiration dates, I believe.
Some people refuse to buy the lites at all, and buy Luna bars or other brands that are nutritionally comparable to the lites. The Lunas cost about half as much as the lites. Funny, I hate the peanut butter lites, but love the Peanut Butter Cookie flavor of Luna bars.
Good luck to you, no matter what you do about the bars!