I use a tassimo machine - works out to 49 cents/cup taxes in, using grocery store brand t-discs.Those things are the biggest scam since bottled water.
I'm sure using a standard coffee perk, filters and a big can of folgers ends up being cheaper, but it's worth it for the convenience of the thing. Throw the travel mug and t-disc in the machine, push the button, put my shoes on, grab the mug/throw out the t-disc and out the door I go. Clean the machine every few days.
I do wish someone would make a refillable t-disc for the thing. Can't be that hard to make.