Since time is the most precious commodity on this earth, invest the time at the front-end so that you can reap the benefits on the back-end. This means putting in a bit of sweat equity and not getting paid today. Rather, you'll get paid somewhere down the road. And you'll continue getting paid whether you keep building that passive income stream or you stop. It's obvious that this is the preferred route, but clearly the road less traveled.
One factor that you must be aware of though is that Care.com is a peer-to-peer arrangement. That means that you will be in direct competition with other pet sitters in your area. You must price your services competitively in order to get business. Once you begin to develop a list of regular clients, you will be in a better position to raise your rates. This will be particularly true as you get referrals from those customers.
eBay is the most popular global auction site around and is a great place to sell items you no longer want. If you are looking to earn some extra cash, start out by looking around your house for things you no longer want; list them on eBay and watch as customers bid on them. You can also purchase clearance sale items and thrift store finds and make a couple dollars profit by listing them as well. The key to selling on eBay is to do your research and find out what the hot items are.