All my single live alone Sims start off as self employed alchemists and abuse the hell out of the elixir shop. I always get to level 10 in a week in that career, make 150k or more, supermax the alchemy, fulfil the alchemy LTW, get to level 9 or better in science, max at least one other random skill, get several other skills started, make 10 or more best friends, and often have two star celebrity level in that first week. Then move on to my goal for said sim. No cheats needed to pull it off ether. The born sellsman, suave seller, elixir store, witch, alchemist combo is the easiest way to break the game wide open. I am addicted to min/maxing in games I play. So I will have to say self employed alchemist is my go to career as I have a hard time matching the start it gives any other way.