What was the original purpose for crack cocaine?

Sometime in the late 1970s, somebody figured out that if you boil cocaine with baking soda and other household chemicals, it produces a rock-like substance that burns at a lower temperature than regular cocaine. This substance is "crack."

Since crack burns at a lower temperature than regular cocaine, it is easier to smoke. And, since crack is essentially nothing more than diluted cocaine, it can be sold at a cheaper price than regular cocaine.

The cheap price is what caused the crack epidemic in the 1980s, as people who normally would not have been able to afford the steep price of a cocaine addiction could now get high every day for cheap.

That is, essentially, the reason it was invented: cocaine is expensive. A cheaper form of cocaine garners more customers. For example, say a cocaine dealer has 50 regular customers who buy from him every day, and 200 other customers who only buy from him once a month, because they can't afford to buy cocaine every day.

Now, say the dealer starts selling crack cocaine, as well as regular cocaine. Now he has 50 customers who buy cocaine from him every day, and 200 other customers who now buy crack from him every day (instead of buying regular cocaine from him once a month).