My group uses a simple system for buying potions and scrolls based on rarity.
![draconian potion of mind draconian potion of mind](https://images.immediate.co.uk/production/volatile/sites/7/2018/08/ERG2EE-0e420d5.jpg)
However, he also maintains a bunch of cheaper concoctions (some real, some not - a luck potion that does nothing, a charisma potion that is just 12 ounces of dwarven vodka) that he sells to folks with less means as an additional way to line his pockets. Most of his valuable potions are ones that would be useful for people from the dark side of the city in their endeavors - gaseous form, invisibility, etc. He has been creating potions that suit the needs of the dangerous types out there so that - should he need to defend himself - he has friends to call upon. However, he lives in fear that the people the nobleman abused with the potions will discover his role. By the time the nobleman was caught by someone offended by his activities, the merchant was able to pay to cover his tracks. One thing led to another and the merchant was able to extort outrageous fees for the love potions from the merchant, allowing him the funds to expand his business. When he tried to expand his product line he was able to start creating Philter's of Love - something that caught the eye of a local nobleman with ill intent.
![draconian potion of mind draconian potion of mind](https://cdn.cloudflare.steamstatic.com/steamcommunity/public/images/items/314660/b740b4b6b45f35d0858dff227a76cb9b54ccdb46.jpg)
He took his knowledge of basic alchemy and magic and was able to fashion a few crude alchemical agents and basic potions and sold them to support himself. He was a wizard's apprentice that failed and was fired. Tables are a great way to generate something on the fly, but if you have time to write questions about it on the forums, you have time to flesh it out from a storytelling perspective. Where did he come from? Why did he start selling? What did he have access to? Who bought it? How much could they afford? How did he make a business of it, and how much has he been able to expand that business? Who are his clients now? Here, you need to start with the merchant's story.