From the introduction:
In the typical fantasy realm you have a great many potions and alchemical formulas with fascinating properties. Some mixtures allow one to fly, others to be resistant to certain harmful effects, others simply allow the wounded to heal. While such potions and alchemical wonders are indeed great, they can often be few in number and costly in fabrication and price.
The common folk of the villages, towns, and even cities typically do not have the coinage that it takes to afford such marvelous concoctions. Despite such currency, however, it seems that a few of the alchemist and potion shops as well as many a traveling merchant or carnival show have intriguing mixtures to sell to such a population at a more reasonable price. Ironically, such potions, cures, tonics, oils, and so forth have marvelous effects that would rival even some of the most expensive of items in the alchemist shop. Or so the labels claim...