Meet the alchemist.
Now whether its a player's stuff, or an npc it doesn't matter. Whether he'd be seeking a Philosopher's stone, trying to make gold from lead or just selling potions of strange origin and even stranger effect its entirely player/GM concern. Still if there IS such a character he needs his stuff! The robe, the big dusty books, the glasses and so on are easy. Buuut there is another bit necessary. You need vials. And test tubes. And something boiling that's making bubbles. Guess that leaves only one choice.
Buy a chemistry set.
There are many on the market and they vary greatly in price and content, ranging from 30-40$ to 200$+.
Obviously 200$+ is too much for a piece of props, so we will aim for a cheaper one. What you need to look for is the content.
Here's what I found in the attic. Its a junior chemistry set that's more of a vintage item if you ask me, hailing from Ye olde socialist days.
It has a ton of vials, most of them still full. All I have to do is change the labels with something more appropriate.
One more thing which I'm going to put in big red CAUTION marks. If you want, you can actually use the contents of the chemistry set to do some simple trick or reaction. That is entirely up to you, just be careful and read the damn manual before trying something. Don't use the vials for useable ingame potions. They are fragile, irreplaceable and were holding(sometimes) dangerous chemicals. For ingame potions that are to be drinkable, there is another solution which I 'll show you soon.