Ad aspera

-- Science is superior to ventilation, ahem! And the university...
But, looking at the guest's displeased face and physique, the alchemist still opened the shutters, albeit covering them with a cloth.
-- So, here's the deal. Tests, ahem. There's a potion of great vigor. Drink it, and you won't sleep for three days, according to my calculations; you'll immediately become flexible, agile, and sharp-eyed. It didn't work out very well last time, but I've adjusted the formula... There's also a potion of sweet dreams. The opposite – you'll immediately lose consciousness and dream of flying in a figure-eight and seducing fairies in the realm of Svidur or whoever you have there. The only condition is that I'll lock you in the basement until it wears off, and then you'll tell me about it, ahem. Ten silver coins for the first test, fifteen for the second. Aha, there's also one with a long-lasting effect – it will make you even stronger than you are now. Ten silver coins. I also have liquid fire. It comes in different forms – you can shoot it, throw it, or adapt it to something like a siphon – ask the blacksmiths about that. Test it on the plants outside the city, and on something, ahem, alive... I'd also test it on some shack in the slums or a village, heh-heh. No one will miss it, I swear by all the gods. I'd rather go with you on that one. Twenty coins for the complete test. Ahem.
Regarding the book... oh, I'm afraid that even if you come in, ahem, presentable condition, you won't be able to negotiate with those highbrow simpletons. But maybe you'll get lucky and find it somewhere else. "On the Transformations of Liquids: Heat and Cold as Part of a Whole" – that's what I need. Or, ahem, the opposite... It's a work by Turanian alchemists. I'll pay thirty-five silver coins if you bring it. I won't cover expenses.
As for the gang... the moneylender won't give me any more loans, and research requires money, ahem. So, I made a deal with the criminals, and they're getting more and more brazen. Not only did they lend me a third of the amount, but they're demanding that I make poisons for them, distill alcohol, and make a bomb. They sense that I have nothing to give them. I had to sell my old house just to pay off half of it. And soon I'll have to pay off the other half. Ahem-ahem. Last time, they beat me half to death and took almost everything I had here. At least they didn't take all the money – I lied and said that if I didn't buy sulfur and saltpeter, I wouldn't be able to make anything else, ahem. In short, get rid of them for me, and I'll pay you ten gold coins. Otherwise, I have a feeling that I'll have to conduct my research in a bandit's dungeon.

Noted:
Merchant Quarter – moneylender
University Quarter – university

Added 8 minutes ago

- Listen, but you don't hear! The Almighty grants blessings, but in return, He requires moderation from us! Whoever indulges in the extreme of gluttony or the extreme of self-destruction treads the path of evil and loses their soul!

-- But what are these blessings? I see money – and I see that it can be exchanged for any blessing. But what does your blessing exchange for?

- Wrong, young man! Suppressing desires is the path of cowards! Cowardice is not a blessing! A truly devout person is capable of controlling all base desires and redirecting their power to good deeds! That is salvation!

-- I don't understand you at all. Now you're saying that the main thing is good deeds. Is salvation in the soul or in the deed?

- He who does not work, neither shall he eat! Give your labor to the Almighty, and He will reward you with food!

-- But my arm is broken, and my legs are crooked. -- the first replies. -- How can I work now?
-- He simply succumbed to greed, -- says the second and goes to beg in the street.

Did they give me any small change?

But they gave something else...