Folger's Coffee packages several of their coffees in K-cups. So, the answer is - yes, just buy Folger's Coffee K-cups. If you're asking - "Is there a coffee maker that will use any coffee I have in a K-cup?" The answer is also, "yes."
Breville makes a K-cup machine that has a ground coffee insert so that you can use any loose coffee you have on-hand. The caveat to that is - it takes a near expresso grind to get the coffee to the correct fine grind level for extraction over the short K-cup brew time. You could not use standard grind Folger's coffee in the K-cup insert as it would make an extremely weak cup with very little flavor.
If you open a K-cup, you will see the grind level you need - and it's nearly powder / espresso grind. If you don't have a grinder that will produce a fine, even grind you cannot get good coffee from the K-cup loose coffee insert.
