Yeah, Kalin is a brewing fiend - I can succeed at anything I touch on him now with herbalism. Yet, I still only give potions out to a small smattering of people. There's just no way to collect enough of everything to make stacks of potions for the selling. Good luck all you non-casters!
Or if you're not a caster and you can't find any potions or varnishes to purchase, jjust make a con-based barbarian. Even if you're dumb as a brick, for some reason you'll just constitution yourself into being the ultimate craftsman! Alchemy, herbalism, metalworking (smelting anyway) and I think even leather working - all you need is the ability to eat day-old sushi without vomiting to be a champion! And you get mega-hit points and more skill points than a fighter! So if you're not going caster, go conbarian.