set sales

My baby dog dog food to eat, when I access the Internet today to help it buy a large package, because now the dog’s appetite is growing, only buy a large package to it can barely maintainweek and a half. Very strange, how to buy dog food to buy but also with dog snacks? I consulted the customer service, said that this is set sales, if you need dog snacks, then you can buy cheaper, do not need it also can be purchased separately dog food. Cheap, then of course I choose a set of buy.