How Small? Well....$20 dollars goes farther than you think.
Go to the bank and withdrawal $20 bucks cash. Put it in an envelope and write the date on it. You now have everything you need to start your own micro business. Below are some examples of micro businesses to get your creative juices flowing:
Antiquing-Go to a garage sale to see what you can find for under $20 bucks. Resell this item on Craigslist or Ebay for a profit.
Walk dogs - Buy some poop bags, doggy treats, and make some cheap fliers.
Hauling- Got a Truck? Put an add on craigslist offering to help someone move, or to take a load to the dump for a profit. Dump fees are $20 in my area, but Yard waste is free, you do the math.
Car Washing - Get some soap, an old towel and a Soft sponge.
Tour Guide- Do you live near a tourist hot spot? Try showing out-of-towners to the local must see sights.
Hobbies - If you already have a hobby like knitting, painting, photography, pottery, tying fly-fishing lures, or have a vegetable garden. Use the $20 to market these products.
Skills - Do you speak another language, know how to cook, understand Math, or great with computers? Try becoming a tutor for others that do not posses the same skill set.
Shine Shoes- Try hanging out in the financial district with some shoe polish, a cloth and a brush.
Bakery- Spread the word to co-workers, friends and family that you are willing to make custom baked goods for any PTA meeting, retirement party, or birthday for a nominal fee.
Find a Micro Business that works for you, and try running it for one month. If you are successful, than you can think about how to earn more. The simplicity of a micro business will earn you money quickly, without the complexities of a small business.