Amazon Prime began as a fast and free shipping program for orders of any amount. Though swift, two-day delivery on millions of items remains the cornerstone of the service, the company has moved into video and music streaming, and cloud storage, which enhances the overall value proposition for those who actually take advantage of Prime's extras.

Amazon Prime members pay $99 per year or $10.99 per month for the privilege, and on Amazon Prime Day—July 11 this year—you'll need to be an Amazon Prime member to take advantage of a wide range of discounts and promotions.

Check out the deals on electronics and home products for Amazon Prime Day 2017.

If you don't have Prime, Amazon offers free standard delivery when you buy $25 worth of "eligible" items.

But there are other incentives to become a member. Prime members now qualify for free same-day delivery on more than a million items, and 1- and 2-hour delivery with Prime Now on tens of thousands of items. Among other key or recently enhanced Prime benefits:

Instant access to video streaming. Membership includes instant access to tens of thousands of movies and TV shows, including Amazon original series such as the Golden Globe-winning "Transparent" and "Mozart in the Jungle," the drama "Bosch," and "Doctor Thorne," from "Downton Abbey" creator Julian Fellowes. You can watch at home on your computer, Fire TV, or other compatible devices.

Music streaming. Prime Music offers unlimited, ad-free access to more than a million songs and thousands of playlists and stations.

Prime Photos. Secure unlimited photo storage in Amazon Cloud Drive.

Access to Lightning Deals. Members qualify for early (30 minutes before everyone else) access to short-term, deeply discounted Amazon Lightning Deals that often feature high-tech and fashion goods.

Kindle Owners' Lending Library. Access to more than 800,000 e-book titles. You can borrow one per month, with no due date, along with one prereleased book per month with Kindle First.

Prime Now. A mobile app that allows customers in most parts of the country to shop from early morning to late night, seven days a week, for groceries, gifts, and food from neighborhood restaurants. Delivery is within 2 hours free of charge, or within 1 hour for $7.99. For restaurant orders, delivery is free within an hour of ordering, and the service is available from Amazon-affiliated restaurants in select areas.

Amazon Family. The benefits include 20 percent off diapers through its service, Subscribe & Save, and 15 percent off eligible products from your baby registry.

Membership Sharing. Two adults living in the same household can create an Amazon Household to share certain Amazon Prime benefits.

You get all kinds of benefits from Amazon Prime.

Why You Might Not Want a Membership

Of course, not everything about Amazon Prime is worth the membership. There's the question of how often you shop on Amazon. If you aren't online much or you don't think you'll take advantage of all the services membership offers, you might as well pass.

If you’re unsure whether Prime is right for you, consider signing up for a free trial. You’ll have 30 days to give it a test drive. But take note: At the end of the free trial, your credit card will be charged the membership fee automatically for the next period unless you cancel in advance.

Paid members who haven't used their benefits are eligible for a full refund. You can't receive a refund if any of the household members have placed a Prime-eligible order. 

Editor's Note: This article was updated with new information, including Amazon's latest pricing.