Paying $119 for Amazon Prime? Don't Miss These 10 Perks

Introduced 13 years ago, Amazon's Prime service has grown by leaps and bounds, with more than 100 million members worldwide as of April. The program, which offers free two-day shipping on an unlimited number of orders for a flat annual fee, has steadily added perks over the years — to the point where some members may be unaware of all the benefits the Prime membership fee (recently increased to $119 a year from $99) has bought them. Here's a rundown of 10 lesser-known advantages of being a Prime customer.

Related: Don't Miss These 13 Perks of Costco or Sam's Club Membership

Even seasoned Prime members may be unaware that another adult living in the same household can be added to the membership and access many of the benefits from their own account. One catch: Payment must be made from the authorizing member's credit card. That may be no big deal if the benefits are shared with spouse or partner, but it could get a bit dicey with, say, a roommate.

That's right, unlimited. And there are free apps available to help upload photos to the cloud. Members also get 5 GB of storage space for videos and other files. Prime members who have run out of room on other cloud storage services — or don't have a backup at all — can breath a sigh of relief.

Free two-day shipping is the most talked about benefit of Amazon Prime, but members also have the option of free same-day delivery in select locations (a growing list). There is a $35 minimum order.

Amazon promises free two-hour delivery from local stores and restaurants through Prime Now, within eligible ZIP codes. The offerings include household items and groceries.

Amazon gives Prime members an early crack at its limited-time "Lightning Deals" — though inconsistent application have some users expressing skepticism. Officially, lightning Deals are good only while supplies last and could mean the difference between scoring a deal and missing out.

Prime members with babies or toddlers can save up to 20 percent on diapers through Amazon Family when they set up a subscription option (which can be canceled or changed) and buying five or more products in a month going to a single address — a requirement added last year. 

Prime members get a discount on Amazon FreeTime Unlimited, a service that offers books, movies, shows, apps, and games designed for kids 3 to 12, with no ads or in-app purchases. Prime members pay $3 a month, a 40 discount from the standard $5 fee.

Prime members (and anyone who shares the membership) can borrow a book a month for free from the Kindle Lending Library. But the book must be read on an Amazon Kindle Reader, Fire Tablet, or Fire Phone, not just a device with the Kindle app. Prime members are also automatically registered for Amazon First Reads, allowing them to download and read select titles a month before the release date for free or at a reduced rate.

With Prime Pantry, members can have grocery and household item orders of $40 or more delivered for $5. Weekly deals and discounts can increase savings. But shoppers won't find the giant sizes available at big-box retailers such as Costco or Sam's Club. Rather, the focus is on regular sizes — a good deal for urban dwellers without a car or extra pantry space.

Prime Day, an annual event when Amazon offers exclusive deals for Prime members, occurred on July 11 in 2017 (beginning late the day before and ending early the following day) and it saw stunning figures: 9.5 million transactions, more than were tracked for either Cyber Monday and Black Friday, according to Hitwise. That's a huge jump from the 6.7 million from the previous year. This year, it's expected to take place sometime around the second weekend in July, so prepare yourself by finding out which Prime Day deals to look out for this year.