Concocting an elixir or pill isn't as easy as anyone thinks, no ordinary person who doesn't have any idea in the field of alchemy won't be able to accomplish that. Naturally, alchemists aren't easy to afford, getting one is extremely hard.
It was not easy to make pills; for every pill concocted, one would need a massive amount of ingredients, and the ingredients are mostly rare. Not only that, even when the quantity measured per component used was extremely accurate, there was no guarantee that the concocted pill would be perfect or successful. There were too many variances: flame temperature, flame control, accuracy of medicinal components, and accuracy of quantities. In some extreme cases, a pill that was made to heal may even turn out to be poison if there was a minor error in the process of making the pill; that was why alchemists were expensive to afford. Alchemists are rare to see or get, so the few ones available would be difficult to get.