How many of you started your own business? Can you share what it is?

I would like to start a business, but I have no idea what I would do. Most businesses for purchase require too much money upfront (20% down payment). If you guys can share any ideas, it would be great. Something that requires less than $50k to start.

Edit: Surprisingly people completely missed the point of this thread. The point of this thread is not how great being an Electrical Engineer is to find jobs. I already work at a fortune 500 company and have an amazing job. I am going to loose my job soon since my EAD expires in 11 months. That's the whole point of starting a business so you don't need to worry about finding a job once your status expires.

What I was looking for: if you started your own store for example, what are you selling? How did you get started? How did you come with the idea?