Many large grocery stores carry Land O Lakes Cocoa Classics by the packet (look in the hot cocoa/cider aisle) but if you want a deal, head down to your local Costco.
They have a 7 flavor pack, with each box containing 6 foil packets. It contains: Arctic White, Caramel Chocolate, Supreme Chocolate, Milk Chocolate with Madagascar Vanilla, Peppermint and White Chocolate, Classic Dark Chocolate and Raspberry Dark Chocolate. At less than $11 this a bargain to be had! That is around 26¢ each, often in grocery stores they are 75¢ to a dollar each. The handy foil packets also means your cocoa won’t get ruined if your food bag gets wet.
PS: They sell the big packages not with the normal cocoa but rather out with the gift baskets of food, next to the gingerbread house kits. Sometimes also on the regular end caps as well.