The U.S. economy is still firing on all cylinders, and that's boosted consumer spending -- and it has been a boon to many retail stocks. But investors looking for the best retail stocks to buy right now need to look beyond some of the companies that are just riding the economic wave to find great long-term investments.

To help you achieve that goal, we asked our Motley Fool contributors for three top retail stocks to buy right now, and they came back with Shopify (NYSE:SHOP), Amazon.com (NASDAQ:AMZN), and Home Depot (NYSE:HD).

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Betting on e-commerce and entrepreneurship

Nicholas Rossolillo (Shopify): This pick isn't itself a retailer, but it is a big supporter and champion of the e-commerce movement. The company provides website management and digital presence services to sellers of merchandise in a pay-as-you-go software-as-a-service package. The boom in digital selling and growth in online merchants over the last decade have been a boon for Shopify.

However, Shopify has also been adding a growing list of merchant solutions to its suite of services in support of small business owners, everything from payment processing to shipping services to credit. Through the first three quarters of 2018, subscription services increased 53% from last year, and merchant services were up 70%. As the end of the year approaches, Shopify expects to hit the $1 billion in annual revenue milestone for the first time.

As Shopify gets bigger, its revenue growth is slowing to a more modest pace. Full-year guidance is calling for about a 56% increase; that compares with a 73% rise in 2017. Nevertheless, just about any other company out there would be more than happy with those kinds of results, especially for an operation the size of Shopify's.

Investor reaction to the cool-off has been to sell. The stock is down 24% from all-time highs as of this writing. The company continues to push forward with new services, though, like its first-ever physical "store" it just opened in L.A. and development of new solutions like inventory management software and a refresh on its app store. With overall e-commerce still expanding by double digits, that puts Shopify in great position to get a slice of the growing pie. Thus, I think investors will be happy a decade from now if they owned a piece of Shopify.

The king of online retail

Danny Vena (Amazon): It's long been known that the bulk of Amazon's profits come courtesy of its cloud computing operation, Amazon Web Services (AWS). While that may have been true in the past, the company's North American e-commerce segment is poised to take that crown.

Operating income margins have improved dramatically across the board so far this year, but margins in North America have tripled to 5.2% during the first nine months of 2018, up from just 1.7% for the same period in 2017. Margins from international operations have also improved significantly even though the segment isn't yet profitable, up to -3% for the first nine months of 2018, up from -6% in the year-ago period. It shouldn't be long before Amazon's international business becomes profitable as well.

This makes the company's revenue growth all the more meaningful, as more profit drops to the bottom line with each sale. For the third quarter, Amazon's e-commerce sales in North American grew 35% year over year to $34.3 billion, generating $2.032 billion in operating profits, just $45 million shy of AWS' $2.077 billion contribution. At this rate, it won't be long before the company's online sales becomes the primary profit driver for Amazon's overall business.

The recent market rout has hit tech companies particularly hard, and Amazon has taken it on the chin as well, falling 25% from its all-time highs reached in early September.

Now's the time to invoke one of legendary investor Warren Buffett most oft-quoted adages: Be fearful when others are greedy and greedy when others are fearful. Now's the time to get greedy with Amazon stock.

Constructing a new future

Chris Neiger (Home Depot): Nearly every retailer has had to retool their business to keep up with the rise of e-commerce -- and Home Depot has done it with great success lately. In the second quarter of this year, the company grew its online sales by 26% from the year-ago quarter, in addition to boosting its comparable-store sales by 8%.

The great news for investors is that Home Depot's management believes there's still plenty of growth ahead, and that full-year same-store sales will be up 5.3% from last year, revenue will jump 7%, and diluted earnings per share will pop 29%.

Home Depot's stock took a hit following last quarter's results, despite all of the good news, and this pullback offers an opportunity for long-term investors to snatch up shares.

The retail industry is far from finished adapting to e-commerce changes, but Home Depot's recent quarter and its full-year guidance show that it's evolving right along with it. Add Home Depot's 2.3% dividend into the mix and investors are looking at a solid retail stock to hold for the long haul.

John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool's board of directors. Chris Neiger has no position in any of the stocks mentioned. The Motley Fool owns shares of and recommends Amazon and Shopify. The Motley Fool has the following options: short February 2019 $185 calls on Home Depot and long January 2020 $110 calls on Home Depot. The Motley Fool recommends Home Depot. The Motley Fool has a disclosure policy.