Buckle up and hold on tight, because it's been a topsy-turvy year on Wall Street. The widely followed Dow Jones Industrial Average and S&P 500 are both firmly in correction territory with double-digit percentage declines, while the growth stock-dependent Nasdaq Composite has plunged as much as 31% from its November peak.

Although looking at the daily loss column in your portfolio during stock market plunges can be unnerving, history is quite clear that buying during these downturns makes sense. The vast majority of double-digit percentage declines in the market don't last long. Further, every notable drop has eventually been wiped away by a bull market rally.

A person drawing an arrow to and circling the bottom of a steep decline in a stock chart.

Image source: Getty Images.

In other words, it's the perfect time for long-term investors with cash to spare to do some shopping. And what better category to target than discounted growth stocks? Companies that offer cutting-edge innovation have the potential to generate life-changing wealth over the long run.

What follows are three discounted growth stocks patient investors can buy and hold forever -- even through stock market plunges.

Alphabet

The first inexpensive growth stock that's begging to be bought and never sold by opportunistic investors is Alphabet (GOOGL 1.20%) (GOOG 1.25%), the parent company of internet search engine Google and streaming platform YouTube.

Shares of Alphabet have tumbled by 27% since hitting an all-time high. The big concern appears to be that historically high inflation and Federal Reserve tightening (i.e., higher interest rates) could push the U.S. economy into a recession. Alphabet generates a sizable percentage of its revenue from ads. Unfortunately, advertising is among the first spending categories to be hit when economic weakness rears its head.

However, fears of a recession shouldn't scare investors away from putting their money to work in this time-tested FAANG stock. If anything, the disproportionate amount of time the U.S. economy spends expanding, relative to contracting, should have long-term investors even more stoked about Alphabet's potential.

Alphabet's foundation continues to be internet search engine Google. According to data from GlobalStats, Google has accounted for between 91% and 93% of worldwide internet search share over the trailing-two-year period.  Holding a virtual monopoly on internet search allows parent company Alphabet to enjoy incredible ad-pricing power.

Beyond Google, which has pretty steadily grown by a double-digit percentage, Alphabet is counting on YouTube and cloud infrastructure service Google Cloud to drive its operating cash flow higher. YouTube is the second most-visited social site on the planet, with about 2.56 billion monthly active users.  Drawing in this large of a crowd has lifted YouTube's ad-pricing power, as well as boosted subscriptions.

But it's Google Cloud, the world's No. 3 cloud infrastructure provider, which could be Alphabet's golden ticket. Google Cloud has been growing sales by north of 40% on an annual basis. More importantly, cloud spending is still in its early innings. Because the operating margins associated with cloud services are considerably higher than those associated with advertising, Google Cloud can be the catalyst that helps to double Alphabet's operating cash flow by 2025.

Excluding cash, shares of Alphabet can be scooped up for about 14 times Wall Street's forecast earnings for 2023, which is incredibly cheap.

Nio

A second discounted growth stock investors can confidently buy and hold in perpetuity is China-based electric vehicle (EV) manufacturer Nio (NIO).

Like most auto stocks, Nio has taken it on the chin in 2022. The COVID-19 pandemic and war on Ukraine have created insurmountable supply chain challenges and parts shortages for the auto industry. China's zero-COVID strategy has magnified these issues by locking down large/important provinces within the world's leading auto market.

While these concerns are tangible, they're not anything that'll alter Nio's strategy or long-term growth trajectory.

Arguably one of the more no-brainer growth trends over the coming decades is the electrification of vehicles. One of the easiest ways for large countries to combat their carbon footprint is to promote the use of EVs. Nio has the growth opportunity of its lifetime sitting on its doorstep.

Despite serious supply chain challenges, Nio's production has been steadily climbing. Two years ago, the company was producing fewer than 4,000 EVs per quarter. Now, it's capable of more than 25,000 EVs per quarter. 

But what stands out most about Nio is the company's innovation. The newly introduced ET7 and ET5 premium EV sedans can leave Tesla's flagship sedans in the dust with a top-tier battery upgrade that produces 621 miles of range. Introducing new vehicles with regularity, and offering plenty of options, has helped boost early stage demand for Nio.

Nio's innovation extends beyond the showroom, too. In August 2020, the company introduced its battery-as-a-service subscription, which allows buyers to charge, swap, and upgrade their batteries in the future. It also reduces the initial purchase price of EVs for enrollees. In return, Nio nets a high-margin monthly subscription fee from buyers, and most importantly keeps early buyers loyal to the brand.

Nio has the potential to deliver jaw-dropping sales and profit growth over the long run.

A hacker wearing black gloves who's typing on a keyboard in a dimly-lit room.

Image source: Getty Images.

CrowdStrike Holdings

A third discounted growth stock opportunistic investors can buy during the stock market plunge is cybersecurity play CrowdStrike Holdings (CRWD 0.22%).

Perhaps the biggest issue for Wall Street to chew on with CrowdStrike is its valuation. When the stock market is tumbling, investors are often warier of paying a premium, even when it comes to fast-growing companies. Even though CrowdStrike's shares are down almost 50%, the company is still valued at roughly 13 times forward-year sales and nearly 100 times forecast earnings for the upcoming year, according to Wall Street's consensus.

But what if I told you this was actually a discounted stock that's seen its price-to-earnings-growth ratio plunge over the past year thanks to sustainable sales growth of better than 35%?

On a macro basis, cybersecurity is something of a no-brainer growth industry. Whereas cybersecurity was once optional, it's evolved into a basic necessity service. Hackers and robots aren't going to take a day off from trying to steal consumer and enterprise data just because Wall Street had a bad day or the U.S. economy is struggling. With businesses shifting their data into the cloud at an accelerated pace in the wake of the pandemic, third-party providers like CrowdStrike have been busier than ever.

The true key to CrowdStrike's success looks to be its cloud-native security platform, Falcon. Falcon relies on artificial intelligence to recognize and respond to threats faster than on-premises solutions. In a typical day, Falcon will oversee about a trillion events. Although it's not the cheapest security solution for end users, the company's gross retention rate, which hovered between 97.3% and 98.1% for nearly four years, illustrates what a popular choice it's become

Arguably the most impressive thing about CrowdStrike has been its ability to get existing clients to spend more. While a five-year compound annual growth rate of around 100% is impressive, what's even more noteworthy is that 71% of clients have purchased four or more cloud-module subscriptions.  A little over five years ago, this figure was in the high single digits. This is CrowdStrike's sustainable advantage, and is all the more reason you'll want hold your shares forever.