I am a huge fan of saving money, but I still like my luxuries. During grad school, when regular caffeination was a necessity, but a financial drain, cold brew coffee was a lifesaver.
This process gives you basically a coffee concentrate than can be stored in the refrigerator. By adding hot water and/or milk, it becomes a sweet and flavourful coffee. Think an Americano or a Misto, but with unbelievably strong (and naturally sweeter) coffee instead of espresso.
1 cup of ground beans (I got mine from Merchants of Green Coffee)
1. Stir ground beans and water in a French press but do not plunge it yet.
2. Keep in the fridge overnight.
3. Press the plunger, and pour filtered mixture into a sealable container.
4. Combine a small amount of the cold brew coffee with hot water. Find your balance, but I find 1tbsp of cold brew coffee is all that is needed for a mug of coffee, and 2tbsp for a larger thermos. Fill the rest of the container with boiled water. Top with milk, cream, and/or sugar.
And there you go! Cold brew coffee will keep easily for a week in the fridge, and will ave you oodles of money when it comes to your daily (or twice, or thrice daily) cup of joe.