The Short Answer
If your book is on Amazon, start with Amazon Ads. They reach people who are already shopping for books like yours, and you can begin with a small daily budget. Use BookBub Ads when you run a discount, especially if you publish wide. Use Facebook ads once you have a series, a strong cover and the patience to test creative, because they work best for building an audience rather than for a single quick sale.
No platform guarantees results. The right first step is to pick one, spend a small amount carefully, measure what happens and only then expand.
The Three Platforms Side by Side
| Amazon Ads | Facebook (Meta) ads | BookBub Ads | |
|---|---|---|---|
| Where ads appear | Amazon search results and book pages | Facebook and Instagram feeds and stories | BookBub's deal emails and website |
| Reader mindset | Shopping now | Scrolling, not searching | Looking for book deals |
| Targeting | Keywords, books and categories | Interests, demographics and lookalike audiences | Fans of specific authors, categories and stores |
| Billing | Pay per click | Usually by impressions or clicks | Pay per click or per thousand impressions |
| Works best for | Any book sold on Amazon | Series and audience building | Discounted books, especially wide |
| Learning curve | Moderate | Steeper | Moderate |
Amazon Ads: Readers Ready to Buy
Amazon Ads put your book in front of shoppers on the store where the purchase happens. Someone searching "cozy mystery with a cat" or browsing a similar author's book page is close to buying, which is why Amazon Ads are the natural first choice for most KDP authors.
You can target specific keywords, competing books or categories, set a daily budget and pay only when someone clicks. Ads also tell you exactly which searches led to clicks and sales, which is valuable information for your book's keywords and description.
Careful management is what makes the difference. In a 2026 Amazon Ads campaign I manage for KDP books, steady keyword work and weekly bid changes produced a 9.63x return on ad spend at a 10.39% ACOS, with $11,315 in sales from $1,181 of spend. Results vary by book, but the method of starting small and scaling only what works applies to every campaign. Our step-by-step guide to setting up Amazon Ads for KDP walks through the setup.
Facebook Ads: Finding Readers Who Are Not Searching
Facebook and Instagram ads reach people while they scroll, which means you are interrupting them rather than answering a search. That makes the ad itself, the image, headline and hook, far more important than on Amazon.
The advantage is reach and targeting. You can show ads to readers interested in particular authors, genres or topics, and build audiences similar to people who already engage with your books. Facebook ads can also send readers to any store or to your newsletter signup, which suits wide authors.
The trade-off is complexity. Results depend heavily on testing several images and pieces of copy, and a single book with a low price can struggle to earn back the cost. Many authors find Facebook ads work best for the first book in a series, where one reader may go on to buy several books.
BookBub Ads: Deal-Hungry Readers
BookBub is a book-deal service with a large audience of readers who sign up for discount alerts. Separate from its selective Featured Deals, BookBub runs a self-serve ad platform where anyone can place ads in its emails and on its site.
BookBub Ads let you target readers who like specific authors or categories, and you can bid per click or per thousand impressions. They work best when you are promoting a discounted or free book, because BookBub readers are there for deals. They are also useful for wide authors, since you can send readers to Apple Books, Kobo, Barnes & Noble or Google Play, not just Amazon.
How to Spend Your First $100
A small budget can teach you a great deal if you spend it with a plan. Here is a sensible way to use your first $100:
- Check the basics first. A strong cover, a clear description and a few reviews matter more than any ad. Ads amplify a good product page; they cannot fix a weak one.
- Choose one platform. For most KDP authors, that is Amazon Ads. For a discount promotion on a wide book, BookBub Ads.
- Set a small daily budget and run the test for long enough to collect real data, rather than judging after a day or two.
- Test a few targets. On Amazon, a handful of relevant keywords and comparable books. On BookBub, a few similar authors.
- Record the results each week: clicks, cost, sales and, for Amazon, the search terms that converted.
- Keep what works, cut what does not, and only then raise the budget or try a second platform.
I set up and manage Amazon Ads for authors, with keyword research, tested ad copy and weekly optimization.
How to Tell If an Ad Is Working
Every platform shows clicks and costs, but what matters is whether sales cover the spend. Track these numbers:
- Cost per click. What you pay for each visit to your book.
- Conversion. How many clicks turn into sales.
- Cost per sale. Total spend divided by sales from the ads.
- Royalty per sale. What you actually earn on each copy.
- Read-through. For a series, how many readers of book one go on to buy the next books.
If your cost per sale is lower than your royalty, the ad is profitable on its own. If it is higher, it may still pay off through read-through on a series, but only if you measure that too.
Which Platform Suits Which Author
| If you... | Start with |
|---|---|
| Publish on KDP and sell mainly on Amazon | Amazon Ads |
| Are running a discount or free promotion | BookBub Ads |
| Publish wide across many stores | BookBub Ads or Facebook ads |
| Have a series with strong read-through | Amazon Ads, then Facebook ads |
| Want to grow a newsletter | Facebook ads to a free reader magnet |
| Have one standalone book at a low price | Amazon Ads with a small, careful budget |
Writing Ads for Each Platform
The same message rarely works everywhere, because readers arrive in a different frame of mind on each platform.
- Amazon. Your cover does most of the work, with a short line of custom text beneath it. Name the reader and the benefit in plain words, such as the problem a nonfiction book solves or the hook of a novel.
- Facebook and Instagram. You need to stop someone mid-scroll. Lead with a strong image, a one-line hook and a clear reason to click, and test several versions, since one usually beats the rest by a wide margin.
- BookBub. Readers want deals, so make the price or discount obvious, and show your cover clearly. Comparing your book to well-known authors in the genre helps readers place it quickly.
Whatever the platform, the promise in the ad must match the book. Ads that overpromise get clicks but not sales, and they invite disappointed reviews.
Mistakes That Waste Ad Budgets
- Advertising before the product page is ready. A weak cover or description wastes every click.
- Spreading a small budget across three platforms so none gets enough data to judge.
- Stopping too early or changing everything at once, so you never learn what worked.
- Ignoring royalty math. Clicks feel like progress, but only profitable sales are.
- Targeting too broadly. Readers of a different genre will click and not buy.
- Never refreshing creative on Facebook, where the same image wears out quickly.
Frequently Asked Questions
For most KDP authors, Amazon Ads are the better starting point because they reach shoppers already looking for books. Facebook ads can work well for series and audience building, but they take more testing.
They can be, especially for discounted or free books and for wide authors who want to send readers to several stores. They are less effective for full-price books.
Start small, with a budget you are comfortable losing while you learn, and run each test long enough to collect real data before expanding.
No. A Featured Deal is an editorial placement you apply for, and BookBub selects only a fraction of submissions. BookBub Ads are self-serve and open to any author.
They can help, but conversions are usually lower without reviews. Building some honest reviews first makes every ad dollar work harder.
Not at first. Master one platform, then add another once you know your numbers.