"I want to start my own business and not work under anyone so I can have more free time (but need money to do so)"
Yeah better turn down a decent position from a successful merchant and start working as a maid for some poor inventors.
She wants quick money without rousing needless attention? Make "flasks" that are basically small lumps of silver or gold and exchange for currency. Make and sell alcohol to a few bars.
She has endless possibilities to make tons of money whilst maintaining a low profile but chooses to do maid and waitress jobs.