While Red Bull may be delicious, you can also add caffeine to your diet by buying kola nut or guarana. Iamshaman.com has kola nut powdered for $.99 an ounce. The guarana is $2.99 an ounce. They're both great flavors. If you make a strong kola or guarana solution, you can use it to flavor rum and cokes and other drinks. A house teaspoon of either is about equal to a cup of a coffee, which makes them a cheaper source of caffeine than any energy or coffee drink.

This place lets you get it wholesale if you want to try reselling it, they've also got bulk extracts with guaranteed caffeine levels. federalabs.com/1kilopricing.htm.

My preferred stimulant is Kratom.. Sometimes productivity boosts are worth using performance enhancing drugs, caffeine or otherwise. My Kratom site is http://www.getkratom.com and please email if you have any questions.

Then there are other drugs that can make you smarter, or at least measurably increase working memory. http://en.wikipedia.org/wiki/Piracetam. Get your nootropics at www.bulknutrition.com.