Most people are familiar with the obvious sources of income in retirement. Dividends, Social Security, and pensions factor into most peoples' plans.

You don't necessarily have to limit yourself to these traditional forms of income in your later years, however. There are plenty of other ways to help fund a nice retirement, even if you're past the point in your life when most people stop working and start relaxing. Here's a rundown of three of the best bets if you're looking to supplement your spendable cash flow later in life...even if you're already in that stage of your life.

1. Continuing to work

You might have moved on from what you consider to be your career, but that doesn't mean you have to stop doing a job altogether. A whole slew of employers are looking for more-mature employees with some real-world experience and a proven work ethic. That's especially the case right now, in light of the nation's labor shortage.

Retailers are particularly keen to hire older workers, although there never seems to be enough qualified educators, either. The federal government also manages programs meant to fill open job positions with qualified seniors, even on a part-time basis.

A retired investor supplementing her income.

Image source: Getty Images.

There is one matter to consider if you do decide to continue your working years with a new (or the same) employer. That is, if you're already receiving Social Security payments, earned wages can impact the amount of your monthly benefit if you haven't yet reached your full retirement age. Above certain thresholds, you'll start forfeiting benefits, although you'll be entitled to a slight bump in your monthly payments at full retirement age based on how much you give up due to excess work income.

2. Renting out a room

If you have space that's not being used, why not rent out a spare bedroom, or an even bigger portion of your house?

These aren't necessarily long-term leases. In fact, it's more profitable if they're not. Lots of consumers are looking to travel, but also looking to avoid costly hotel stays. They'll pay pretty good money for a less-conventional place to stay, though, including someone else's home.

And getting started with such a venture isn't difficult to do. Companies like Airbnb (ABNB 0.10%) and VRBO manage websites that allow property owners to connect with travelers. Those platforms will take a small portion of your fee, but they're worth it in that they attract thousands of travelers.

Depending on where you live, short-term landlords can collect on the order of $1,500 to $3,000 per month on just one property.

3. Selling online (or offline)

Technology and the internet haven't just made it easier to find or rent lodging. They've made it easier to buy and sell pretty much anything. Just look at Amazon!

You don't have to become the next Amazon, however, to make some good money by selling stuff online. eBay (EBAY 0.31%) was built from the ground up with smaller sellers in mind. Meta Platforms' Facebook Marketplace or even Craigslist are also great ways to notify prospective buyers that you've got something to sell.

But you don't know what to sell? Don't sell yourself short. Everyone has a hobby or specialized knowledge that makes that person an expert on something. Use this knowledge to buy and then resell goods for a profit. Specializing in one particular sort of product like baseball cards or antique furniture could be more profitable than selling a little bit of everything.

4. Writing

Finally, add writing to your list of unexpected sources of retirement income.

That's a fairly broad suggestion, but no less broad than your range of options when it comes to penning words for profit. Blogging about your personal experiences with a particular subject matter, contributing commentaries to news sites, and even creating fiction are all viable possibilities. Obviously you must have a modest degree of talent for the art of writing -- even writing simple news stories. Like most other skills, though, this is one that can be learned. It's also not work that requires perfection.

It's unlikely you'll get rich doing gig writing work, part time or full time. New bloggers might make only a few thousand dollars per year even with a consistent, ongoing effort. Self-published book authors typically earn even less.

But it's a business in which increasing quality and quantity coupled with the passage of time can beef up earnings. Better still, being a writer allows you to work when and where you want, doing something you love (or at least love to talk about).