- Pet sitting 4-5 dogs at a time (I made $20-$25 a night per dog when I did it depending on size and they provided their own food). Babysitting two kids for 7-10 hours can earn you $100 Picking up dog poop for 10-20 different families depending on your rate. Sell your unwanted stuff on Craigslist. Conduct a yard sale and sell stuff there. Use your blog, if you have, to sell 10-20 products as an affiliate. A couple of college friends made $100 or more a night for being designated drivers pretty much – they carted inebriated college kids from bars/clubs to their rooms for $5-$10 per person depending on the distance. Just 3-4 car loads and they were golden.
Method 1 One method is to spend a full day building a small blog with several well written informative posts in a fairly profitable niche, and doing some marketing. Submit it to some of the bigger blog directories, and submit some of the posts to article directories so that some automatic link building can be done over time.
Submit all posts to relevant blog carnivals. Also, socially bookmark every post on as many places as you have time to do so. Place some Adsense on it and maybe a few affiliate products. Then leave it. It might take a few months to get your $100, but it will still be as a result of one day's work. If this works well for you then there is nothing to stop you from keep creating one of these every day.
Method 2 If you can play a musical instrument, then try busking. I hear that you can easily make $100 in a day if you find a decent spot.
