Lay’s newest potato chip flavors, Bacon Mac & Cheese, Wasabi Ginger, Mango Salsa, and, yes, Cappuccino, hit stores today. These chips, which have already received myriad mixed reviews, are part of the company’s “Do Us a Flavor” contest. The winner will stick around, while the other three will eventually vanish from shelves. If you can’t immediately track them down in your local store, however, don’t despair—just open a web browser. Last week, even before the chips officially went on sale, they were fairly easy to track down on the secondary market. On Friday, single bags were listed on eBay for a $11 a pop, plus $6 shipping (the suggested retail price is $4.29). Amazon also showed some options, including a four-pack of the Cappuccino chips for $24. And as the snacks become easier to find in retail stores, the rules of supply and demand should kick in, dropping prices. Dig a little further into this snack food grey market, though, and you find plenty of options that won’t be popping up on shelves any time soon. One optimistic eBay seller lists a $49 bag of Lay’s Chicken & Waffles flavored chips, one of last year’s “Do Us a Flavor” contest runners-up, which has since been discontinued. You’ll also find other snack chip rarities, such as a $40 bag of Doritos Jacked Test Flavor 404, which one review described as tasting like “oniony vinegar” or “dry cat food,” and Pringles Pecan Pie, a seasonal special from the 2013 holidays, listed at $20.50 for two cans. If chips aren’t your thing, you might be more interested in a $15 pack of Root Beer Float-flavored Oreos (a new variety that’s reportedly beginning to appear in stores), or $15 bottle of Coca-Cola Blak, a coffee-flavored cola put out of its misery way back in 2008. Marvin Nitta, editor of food review blog TheImpulsiveBuy.com, says that when the limited editon Lebron James Mix 6 Sprite soda came out earlier this year, he saw online sellers listing it for “four or five times the regular price.” (Currently, you can pick up a can on eBay for a cool $12.) Eric Huang, who writes about snacks on his blog, Junkfoodguy.com, says he thinks the secondary snack food market is driven, in part, by companies’ recent attempts to try out more bold and attention-provoking flavors. Wacky flavors make the news, and adventurous eaters want to sample them, even if that means paying a premium. The fact that they’ll eventually vanish only makes them more enticing. In fact, Huang has his own “white whale”: a Doritos flavor called Wild White Nacho. He says he tried the chips once back in 2007, when they were briefly on the market as part of a contest, and “I’ve been searching ever since.” International snacks are another thing that drive curious eaters to buy pre-owned junk food, says Huang. American foodies are understandably curious about foreign fare like Lay’s Lobster Hot Pot (3 bags for $25 on Amazon) or Canada’s uber-spicy Doritos Roulette (on eBay listed at $21 a bag). There are some clear downsides to buying secondhand snacks. Between the mark-ups and shipping costs, you’ll pay more than you ever imagined for junk food. Many of the rarest discontinued products are well past their sell-by dates, though some food scientists say we shouldn’t get too worked up about that. There’s also the squashing and crumbling factor: Not surprisingly, many Amazon shoppers complained that their chips were nothing more than florescent orange dust by the time the snacks arrived on their doorsteps. Then there’s the unpredictability factor. Nitta recalls buying some fried chicken-flavor Doritos from a seller in Japan that were confiscated by customs because they contained an ingredient that’s illegal to bring into the country. Plus, he says, “in the back of my head, it makes me feel weird to buy food from some random person on the internet.” If the groundswell of eaters chasing a product gets large enough, it can occasionally help put the items back on the market. Earlier this July Hostess announced the return of the Chocodile, a chocolate-covered Twinkie that was discontinued in the late 90s. In a statement, the company said the elusive snack had “inspired a black market following,” while NPR reported that the creme-filled sugar bombs have been listed on eBay for as much as $90 a box. Still haven’t seen any flavor tempting enough to prompt you to buy some gently used junk food? Just wait: The winning submissions to “Do us a flavour,” the Canadian version of the Lay’s contest, will be announced in August.