there's plenty of ways to make money without having a mod. For instance if you build a pond and you have Seasons, which undoubtedly @TadOlson has, because I know you like gardening, you can catch fish and sell them. Ponds aren't expensive to build, and you only need a small one, @$1 a square/depth. The fish are free, and you only need a cheap barbeque to cook them and eat them for free.
Another one is the gardening it'self. And then with open for business there's endless possibilities. And you can always go to community lots and cook yourself free hotdogs and hamburgers.
And then there's the townies, npc's and if you're not doing a strict legacy, the premades too, to merely move into the household for their money and then boot them out when you're done with them, which is allowed in a strict legacy. If you read the legacy rules, you will see that you don't have to marry sims for them to join the household nor have their baby, you can just move them in, and move them out again at any time, but you can't move them back in after that. You could put them to work instead of your sim.
If you find Mr. Big, or Femme Fatale, they are worth $70K. Mr. Big has black teddy boy hair and wears a red smoking jacket. Femme Fatale looks like a Bella Goth wannabe with black hair and a slinky black dress. Oh, but they come with Night Life, pretty sure.