Here's a silly little business idea that I had.
Feed stores often sell chicks (chickens, turkeys, ducks), and must tend them until they're sold. Of course, the people who work in feed stores aren't the most motivated, educated, or enthusiastic bunch.
An agreement with the feed store to tend the birds daily, in exchange for first option to purchase leftover chicks when new batches arrive (they usually sell them for $1 each - often a 90% discount - to make room when new stock arrives).
Tending the chicks gives 1 product: manure, which can be sold or cultivated.
Purchasing old stock gives a heavily discounted product that you can either grow or sell. A fully grown bird can fetch between $25 and $50 (depending on breed), or you could sell them immediately - leveraging the 90% discount you received.
For the feed store, it's a win-win situation. They will have fewer losses (death) due to neglect, their employees will be free to take care of other store business, and they aren't losing anything by selling them to you for their normal liquidation price.
It's a lot of work, for sure.