My 4 ideas for a side business to diversify income

Lately I've been thinking about ways to earn extra money through a side business.

It's not that I'm going broke, I'm just looking to apply the concept of stock diversification to my income stream.

Ideally, I'd like multiple sources of income coming from multiple places.

As a self-employed writer, I'm already diversified: My income comes from as many as two dozen different publications and websites.

Almost every year, budgets get cut and I lose a client or two. It hurts, but it's easier to deal with replacing 10% or 15% of your income than all of it.

I also earn a little bit of money from my stocks (dividends and capital gains) and a few bucks (literally) per year in bank account interest.

But I'm looking to diversify outside of my field.

I also need something relatively passive because I can't afford to take time away from my writing business.

The first thing everyone suggests is rental property.

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I've thought about it.

There are two small houses on my street that would make great rentals. It has great long-term prospects but too much short-term risk for me.

Even if I had $30,000 to drop on a down payment, I'm not ready to tie up that kind of money in a piece of property right now. Plus I really don't want the hassle of being a landlord.

I'm looking for a side business that I could start for $5,000 or less.

Ideally, I would have to spend no more than a few hours per week and be able to generate a few hundred bucks per month within a year.

I understand these might be unrealistic expectations, but I'm flexible.

I've been reading a number of books including The $100 Startup: Reinvent the Way You Make a Living, Do What You Love and Create a New Future.

The author interviewed 1,500 people who became "unexpected entrepreneurs" after discovering an unfilled market niche.

The book highlights a number of success stories, including photography businesses, websites and home-based web retail operations.

I've thought about a few ideas in the past couple of years, including:

In any case, with the state of the economy far from certain, I think we should all seek out some type of passive income.

I may run through 100 ideas before I find something that will work, but I'm going to keep looking.