You can
Become:
A sculptor
A journalist
A politician
An actor/director
Or
(My personal favorite) Just quit your job. Give your sim a break! My sims haven't even reached 100,000 simoleons and they are just fine. They -suspiciously- have 7 cars, a HUGE house, and 7 people living in that house. And NONE of them have jobs! Honestly, I even spoil them. Whenever I do get money, I spend it on buying a house for my Sims who move out. Stupid idea, I know. They should just get a job.
(And no, I did not use cheats to get the house, cars, etc.)