I know a guy who rebuilds fuel pumps for gas stations at home. I doubt he has more than $5000 in the business.
If you have a few bucks, the room, and a little mechanical skill (you'd be surprised at how little you really need) you can buy wrecked cars, fix them up and sell them.
I know people who do on-line customer service from home. I also know several collectors, but you need to have the stomach for the business.
I have a pretty extensive shop and an A&P mechanics' license, so I find basketcase aircraft from time to time, clean them up and then sell them.
If you can write, there are opportunities to build resumes and edit term papers and some kinds of commercial writing on-line.
My wife once worked as a personal shopper for 2 years, which was a really cool job that she loved.
I would think that you're only limited by your imagination, here.