If you're willing to put some effort into procuring items for sale, you may be able to make quite a bit of money buying and selling. The secret is to look for bargains at places like flea markets, garage sales, and second-hand stores, and then sell the items for more online. This works well for items like books, which are relatively easy to store and ship.
Or you can take dog walking a step further and get paid to take a dog in while the owner is away! Have you ever checked to see what it costs to board a pet? Those places are not cheap! Do some research and charge 10 – 20% less. Post your ads on Craigslist or around town. But don't expect people to just leave their loved one with a stranger. Make sure you offer your references and that you have all their necessary information if Fido gets injured or sick. Rover can help you here, too – Become a Pet Sitter.
If you’ve got some free time and don’t live in the middle of nowhere, becoming a Lyft driver can be a very lucrative side hustle that allows you make money fast. And right now, they’ve got a promotion going on where any new driver will instantly get a $300 bonus after completing their 100th ride. If you start now and hustle hard on the weekends, you can probably unlock that bonus within a few weeks of driving (and that’s in addition to your normal earnings).