6 Ways to Earn Passive Income When You're Retired

If you're looking to pad your bank account or stretch your retirement savings without working longer hours, passive income could be a good option for you. Passive income is money you earn that isn't directly tied to the hours you work.

You might need to commit time and energy upfront before seeing the fruits of your labor. Depending on the gig, it could take weeks, months or even years to set up a reliable passive income stream. Passive income earnings can also ebb and flow, and the IRS will take a cut for taxes.

However, passive income has many benefits for retirees. It can provide you with the security of an additional income stream. You also have the freedom to pick the hours and projects that fit your lifestyle.

[Read: 6 Ways to Diversify Income Streams in Retirement.]

Whether you want to cushion your retirement fund or make some extra spending money, here are six ways you can earn passive income.

1. Use cash back apps. Some apps allow you to earn money back on items you buy. For regular purchases like food, this is a great way to bring in some extra cash as you shop for necessities. Once you download the app and follow the instructions, you may receive a portion of the purchase price back. Other services allow you to earn cash back on your online purchases. You'll want to make your shopping list ahead of time and stick to rebates for items you actually need to avoid overspending.

2. Write an ebook. Whether you plan to pen the great American novel or your own memoir, consider writing a book. You won't need an agent or a connection to a traditional publishing house if you check out self-publishing. After you write a book and upload it, you'll continue to make money with each copy you sell. Services like Amazon's Kindle Direct Publishing platform make it easy to self-publish your ebook, and you can earn up to 70 percent royalties on your sales. You could also publish your book as a paperback, but you'll see fewer royalties and be responsible for printing costs.

[See: 10 Tips for Working in Retirement.]

3. Sell your photos. If you have a knack for taking good cell phone pictures, you could make money selling your original images. Foap is a free smartphone app that allows you to list photos for sale. If someone buys your image for $10, you'll walk away with $5 after Foap takes its cut. If you upload many different images, you could catch the eye of someone in the market for a particular photo. You can also add tags to your image to increase your chances of having your photo picked up. For example, you could tag a photo of your dog as "dog", "pet" and "beagle" to boost its chances of showing up in searches. Also, instead of heavily edited or filtered photos, you'll want to focus on taking crisp, yet realistic images.

4. Rent out your extra space. If you have an extra room or space in your home, consider renting it out. Retirees who live in major cities or popular vacation destinations should be able to find a regular stream of customers. You can manage the listing yourself or outsource that responsibility to a management company. However, some ongoing effort might be required on the part of the homeowner. Some hosts clean and prepare the rooms, while others outsource the job. It's up to you whether to spend time with your guests or be a tour guide.

5. Put ads on your car. Imagine making extra money as you drive around town. Carvertise pays approved drivers to place removable advertisements on their vehicles. Typically, drivers need a clean driving record and must be on the road a certain number of miles a day. If you drive a lot in retirement, this gig could defray some of your travel costs.

[Read: 10 Resume Mistakes That Make You Look Old.]

6. Start a blog. If you have a niche topic you want to write about, consider starting your own blog. In addition to writing about subjects you're interested in, you will need to create a community and build a following. Once you're up and running, you can look into running advertisements on your blog or making money with affiliate links. However, the Federal Trade Commission has strict guidelines regarding advertising on the web, and you must disclose if you could make money off a link on your blog. You can also offer sponsored blog posts, courses and ebooks on your site to create additional revenue streams.

Kathleen Garvin is an editor at The Penny Hoarder.

Kathleen Garvin is an editor at The Penny Hoarder, a personal finance website that covers a variety of ways you can save and make money. You can follow her on Twitter @itskgarvin.