If you throw a gold-level House Party you get the 'landlord whisperer' as a reward in your household inventory which is worth $1,880 to sell (so you might spend $100-$200 putting on a party, and get a really good return, with all the social benefits of the party). Each party (and dates) has a different reward for each level of success. I've found gold house parties to be great for that - one sim was basically a freelance Event Manager (in a Settler Challenge with careers not yet allowed, she made a killing).
As others have said, harvestables. I find the time investment worth it - I've found roses particularly lucrative.
