Remember cost and benefits.  I'd only need poison on enemies that are worth the expense.  I doubt that I'd need much at a time, maybe three doses worth.  After all, I'm looking to make a profit too.  You might want to work on things that enhance armor piercing or inflict other status anomalies like blindness or paralysis.  There's also the potential for impact explosives applied to an arrowhead or thrown weapon.

Maybe, potions for drinking, poisons for single use weapon effect modifiers, tinctures for time duration gear modifiers, and oils for regenerative effects for durability or maybe pet alteration effects?[@Zelosse]