I periodically check the k-cup prices using that way-cool Amazon discount-finder on the right sidebar. Here’s the best prices I see so far:
San Francisco Bay Coffee Decaf One Cup for Keurig Brewers, French Roast, 36-Count is only $16.62 after Subscribe & Save, or 46¢ a cup.
If you use your machine for everything, here’s a great deal on hot cocoa: Grove Square Hot Cocoa Cups Variety Pack, Single Serve Cup for Keurig K-Cup Brewers, 12-Count (Pack of 3) is only $8.83 or 24¢ a cup!!! This is also available with FREE shipping for Prime members.
No K-cups but still want cheap(er) coffee? How about this The Bean Coffee Company Organic Ground Coffee, Egg Nog, 2.25-Pound Bag for $12.64 using Subscribe & Save. That works out to 35¢ an ounce, which is very cheap for organic, flavored coffee (just think of the prices you pay for those 10-12 oz bags at the grocery store).