Most investors dream of "life-changing" stocks -- investments that deliver such huge returns over the years that they really do change the way we live.

Many of us know someone who had the combination of foresight and luck to buy a tech giant's stock in its early days, reaping huge profits as the company grew to prominence. We asked three Foolish investors to name companies that they thought might have life-changing potential at today's prices. Here's why they chose Shopify (NYSE:SHOP)Universal Display (NASDAQ:OLED), and a company that has already changed a lot of investors' lives, (NASDAQ:AMZN)

A person is shown holding a credit card while using a laptop computer.

Image source: Getty Images.

An online-retail innovator 

Keith Noonan (Shopify): E-commerce is changing the world, and while media coverage and personal experience might make it seem like everyone already does most of their shopping through and other online outlets, the U.S. Department of Commerce reports that online sales accounted for just 8.9% of the retail market in the second quarter of 2017. That points to a big opportunity for Shopify.

What started as a site for selling snowboarding equipment has since evolved to become the leading e-commerce service platform for small and-mid-size businesses, and Shopify has the potential to accelerate, and benefit from, the online-retail transformation. The company provides and manages customizable online sales portals, which offers a huge value to enterprises that might not have the resources to handle those tasks in-house.

In addition to generating recurring revenues from its business clients, Shopify also receives a cut of the sales made through its platforms, a dynamic that promotes rapid revenue growth as it adds customers -- and one that could prove very rewarding for shareholders. The company recently announced that it now provides sales portals for more than 500,000 business, and its customer base has grown at an average annual rate of 74% since 2012.  Last quarter, revenue increased 75% year over year, and while the company is not yet profitable, it should be able to easily become so when it pulls back from its big growth push. 

Even though the stock has gained more than 140% over the last 12 months, Shopify's $10 billion market cap still leaves room for explosive growth that could deliver life-changing returns for investors.

Amazon has already changed lives, but there's more to come

John Rosevear ( Keith made a good case above that there's still massive potential for growth in online shopping with Shopify. And while it's already huge, I'd argue that the same case means there's still room for mighty Amazon to grow from here -- significantly. 

Amazon has already been a life-changing stock for investors who saw its potential and bought early on. But what continues to impress me about the company is that, a full 20 years into its history, it's still chasing (and finding) serious top-line growth.

Amazon's revenue was up 25% to $38 billion last quarter. Of course, we talk about revenue growth because profits are hit-or-miss with this company. That's a function of CEO Jeff Bezos' relentless determination to reinvest in new opportunities and new technologies that have the potential to make it even bigger and better over time.

But consider the foundation it's building on at this point: A colossal online-retail presence that is still expanding into new categories (like automobiles and groceries), a cloud infrastructure business that is hugely profitable and growing, and artificial-intelligence expertise that will open new doors for new businesses -- with more coming all the time.

A Boeing 767-300 freight airliner with Amazon's "Prime Air" markings, in a hangar.

Among many other things, Amazon is investing in ways to cut delivery times -- including its own cargo airline, Prime Air. Image source: 

There is some risk here: Amazon's stock isn't exactly cheap at the moment, and it could take a sizable hit if the overall market turns bearish. But with its already-huge presence and plenty of growth paths open, I think this is a company that investors will want to own for a long time, through the market's ups and downs. Amazon's stock has already changed lives, but it could change many more investors' lives for the better in the years ahead. 

Don't be fooled by Universal Display's recent gains

Steve Symington (Universal Display): Make no mistake, Universal Display has already delivered mammoth returns for many investors. Shares of the OLED technology specialist have climbed 630% in the past decade, including a 98% return so far this year alone. Its flagship technology is already found in the displays of hundreds of millions of smartphones and tablets -- most of which were manufactured under its long-term license and material supply agreement with Samsung Display. And fellow Universal Display customer LG Display recently announced a roughly $7 billion investment aimed at ramping production of its next-gen OLED televisions, which should leave Universal Display's coffers even more flush. But I think Universal Display is just getting started.

For one, keep in mind that on Sept. 12, Apple is widely expected to unveil a premium iPhone model with an OLED display, marking its first-ever departure from LCD displays in its most popular product line. Here again, Universal Display is poised to benefit as its customers are the ones producing those displays.

What's more -- and arguably even more exciting -- Universal Display's OLED technology is poised to disrupt the global lighting industry in the coming years. Its various lighting customers -- including Philips, LG Display, OSRAM, and Acuity Brands -- are all working on their own early-stage OLED lighting solutions, some of which can already be found at major retailers like Home Depot (NYSE:HD). As the cost of OLED lighting panels falls and their efficiency continues to rise, eventually they should reach a tipping point where OLED fixtures represent a more compelling option than today's lighting solution of choice in directional LEDs.

Finally, as I pointed out a few months ago, note Universal Display only just initiated a $0.03-per-share dividend earlier this year. Management called it "a good place to start," noting they "intend to continue to pay regular dividends quarterly going forward." For investors willing to buy now and collect those dividends as they grow and Universal Display's long-term story plays out, I think life-changing returns are certainly possible from here.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.