Audible is easily the largest marketplace for audiobooks, but it's also pretty expensive. Here are a few ways you can reduce the cost of expanding your audiobook collection.

At $14.95 per month, a standard one-credit Audible subscription is more than a lot of unlimited media options (like Netflix or Amazon's own Kindle Unlimited) for just a few hours of content. You can lower that per-item cost by buying a more expensive plan or paying yearly, but even so, there's nothing even close to an "all you can eat" option for Audible's vast selection. And purchasing audiobooks outright outside of the monthly token system is expensive, with most professionally published audiobooks costing $20-30. It adds up quickly.

Some alternatives are considerably cheaper or even free, like Scribd or digital rentals from your local library. But nothing beats Audible's selection, which is probably why it's so expensive. Here are a few ways you can mitigate that cost.

Take Advantage Of Audible's Free Trials

New users of Audible get access to the standard "30-day free trial." In Audible terms, this means one free credit, which you can exchange for almost any audiobook on the site. You'll have to provide credit card information (or point to your Amazon account) to get the free credit, but if you cancel before one month, you won't be charged. Audible credits, and the books for which you exchange them remain connected to your account even when you don't have an active subscription.

You should cancel your trial account before the time limit expires, even if you intend to keep buying books. Why? Well...

Cancel Your Account (Or At Least Pretend To) Every Once In A While

With Audible, as with other services, the company wants you to keep you paying on a regular basis. To incentivize you to keep your account active, they'll often offer you a discount if you try to cancel at the end of the month. On multiple occasions after canceling a month-to-month subscription, Audible has offered me a 50% discount on the next three credits. That's three audiobooks---generally $20-30 when bought individually---for under $8 each.

You can't merely threaten to cancel your account every three months and score a half-price subscription forever. But unlike the initial free trial (which won't work more than once for the same account), Audible's customer retention system seems to reset periodically. You can certainly pull this move once or twice a year to score some cheap credits, especially if it's been a while since you've had an active subscription. And don't worry: even if you're not offered a discount, there's no penalty for canceling and subscribing again immediately.

Watch For Sales On Audible Credits

In addition to the standard free trial, Audible will often offer a discounted limited subscription for "new" subscribers. That "new" is in quotation marks because despite having an on-and-off subscription for years, I've managed to sign up for these discounts on an inactive subscription multiple times.

These discounted initial subscriptions are often $5 for three months, a 66% discount. Sometimes they require you to be an Amazon Prime subscriber, sometimes not. But you can combine them with the "threaten to cancel" technique above to score half a dozen audiobooks for just over $35 (versus $75 for six standard Audible credits, or $100-180 versus buying major audiobooks at standard prices).

Shopping blogs and discount sites like Slickdeals and Groupon are places that generally feature these discounted limited subscriptions. Check in on them on a regular basis, or follow them on social media. "Prime Day" generally has at least one major discount for Amazon Prime subscribers, and sometimes Audible will offer currently-subscribed members one to three extra credits for an immediate, discounted rate.

Keep Audible's Emails Enabled

Yeah, spam emails are annoying. But If you're looking for discounts on Audible audiobooks, you might want to let them through anyway. The reason is that in addition to standard credit token sales, Audible also sells standard audiobooks at regular prices, available to purchase whether you're subscribed to monthly credits or not.

And just like any other conventional retailer, Audible often has sales on its standard, non-credit prices. You'll see periodic discounts on individual books, but what you're really looking for is big sale events that will offer dramatic discounts on hundreds of books at once, ensuring there will be at least a few that match your listening interests. Often these titles are discounted by up to 75% versus their regular prices, coming in well below even the rough $15-per-book that a monthly credit scores you.

Above is an order I made in July: four books for about $28 total, during one of Audible's standard price sales, all paid for with an immediate charge instead of Audible monthly credits. If you checked the regular prices today, those four books would cost about $91 together. Not bad.

In addition to individual discounts and large-scale sales, Audible will often offer discounts via email or credits for actions like pre-orders or writing reviews. The site will also let you know if a book you might be interested in is part of a promotion like the Daily Discount. It's well worth the occasional clutter in your inbox.

Check Your Kindle Books For Discounts

People who enjoy digital audiobooks generally enjoy ebooks as well. If you have a book in your Amazon Kindle library that's also offered as an Audible audiobook, you can often "upgrade" with an additional Audible purchase at a significant discount off the price of the audiobook alone. Check your Kindle app on your phone in the "More" section to find these offers.

The combined price of the ebook and audiobook is generally around the same, so purchasing the ebook specifically for a discount usually doesn't make sense. But if you've picked up the Kindle book on sale, or if you're just looking to enjoy an older book you haven't read in a while in audio form, it's worth a look. Independent authors who publish their books digitally (and usually very cheaply) often offer audiobook upgrades for just a few dollars. This comes with the bonus of being able to switch between the ebook and narrated audiobook at any time, with your progressed synced.