One way to save money fruit juices and drink mixes is to cut them with water.  With orange juice, I fill the glass with 25-33% water and then pour the OJ into the glass-- you won't notice any real difference.  With drink mixes I usually short scoop the recommended scoops.

Another approach I use is to do what I call "One-for-Ones".  This helps me drink more water thereby saving money by not blowing through the juice as quickly.  I simply drink a glass of water before each glass of juice.  This will help fill me and I drink less juice in one sitting.

Bonus:  These tips not only save money, but they are more healthy-- more water, less sugar.

Drink up!