If you don't want to level the Scientist career, I've found an interesting way to make money when I was messing around with the photo station. If you place it on a retail lot, you automatically get money every time you select one of the "Take Photo..." options and choose sims. It doesn't matter if the store is open or even complete (has a cash register), or if the sim you're taking a picture of is in your household. You don't even need to take any actual pictures of the sim- though I would suggest doing so, as you can sell the photos for extra money.
It doesn't make too much money, but the amount increases as your photography skill improves. And besides, with some quick pausing skills, you can easily spam the interaction for a few hours and the money will quickly build up. While probably not as effective as cloning, you can do it as soon as you enter a new game and it doesn't require the Scientist career.