$8 Cranberry Juice

This year, I developed a new drink that I enjoy, but I am not sure how sustainable it is, due to cost.  The recipe is simple:

1) Get a large glass (plastic if near the pool, glass if inside)
2) fill 1/2 to 2/3rds with ice
3) cover ice with organic cranberry juice - real cranberry juice, not pear or apple or other juices with some small percentage of cranberry in it, but actual real cranberry juice like R.W.Knudsen 100% Organic Cranberry Juice
4) add one or two (or three) shots of Costco vodka or Cruzan rum
5) put in either organic Stevia, or, organic Trader Joe's pineapple juice, to sweeten

All of these ingredients are cost effective, except for the organic cranberry juice, which is running $8 a bottle at WholePayCheck, Trader Joe's, and at Gelson's market on the PCH.  Large chain grocery stores (like Ralph's and Albertson's and Von's) don't appear to carry any 100% cranberry without added sugar or HFCS.  Oh well.  The tart cranberry does promote healthy renal function, and the Stevia makes it very low calorie, while the ethanol does help one fall asleep before 9pm to get up at 4am... but I need to find a more sustainable source of cranberry juice.