High inflation and rising interest rates pulled the Nasdaq Composite into a bear market last year, and the technology-heavy index is still 27% off its high. That drawdown wiped away trillions of dollars in wealth, but it has also created a buying opportunity for patient investors. To quote Warren Buffett, "The best chance to deploy capital is when things are going down."

With that in mind, shares of Roku (ROKU 1.00%) and PayPal Holdings (PYPL 0.10%) are down 86% and 75%, respectively, but the future still looks bright for both businesses. Here's why these growth stocks are worth buying today.

Roku: A leader in streaming entertainment

Roku reported disappointing financial results last year. Revenue increased just 13% to $3.1 billion and cash flow from operating activities dropped 95% to $11.8 million. But that dismal performance can be traced back to temporary economic headwinds. Specifically, many brands reduced their ad budgets to compensate for the decline in consumer spending brought on by high inflation. That situation should resolve itself in time, though, and Roku is well positioned to reaccelerate growth when that happens.

The company is following in the footsteps of Alphabet. Much like Google Search is the onramp to the internet, Roku is becoming the gateway to streaming entertainment. Its superior operating system and reputation for affordability have won favor with consumers. In fact, Roku is the most popular streaming platform in the U.S., Canada, and Mexico as measured by hours streamed, and it ranked as the fastest-growing brand (in any product category) among Gen Z and millennial consumers last year.

Streaming still accounts for a relatively small portion of television viewing time, but Roku is perfectly positioned to benefit as more consumers cut ties with cable and satellite. To quote company president Charlie Collier: "Roku is not just another player in the streaming wars, but the streaming wars are actually being fought on the Roku platform, and that is a tremendous advantage."

Indeed, online video ad spend is expected to increase at 14% annually to reach $362 billion by 2027, and Roku is perfectly positioned to benefit. But the company also generates transaction-based revenue when viewers purchase content through its platform, and it recently partnered with Walmart and DoorDash to bring shoppable ads to its platform. Roku also launched new smart home devices in the fourth quarter, including cameras and video doorbells, and it plans to monetize those products with services like cloud storage and AI-based alerts.

In a nutshell, Roku is already well positioned to benefit as brands spend a larger portion of their ad budgets on streaming video, but the company is also experimenting with adjacent revenue streams that extend its market opportunity. In that context, shares look relatively cheap at their current valuation of 2.8 times sales. That's why this growth stock is worth buying.

PayPal: A leader in digital payments

PayPal faced significant economic headwinds last year, but management reacted quickly by cutting costs and refocusing investments on its digital wallets and checkout solutions, two areas where the company benefits from a strong competitive position. Those efforts have already produced tangible results. While revenue increased just 7% to $7.4 billion in the fourth quarter, PayPal managed to cut $900 million in expenses throughout the year, which resulted in non-GAAP earnings growth of 11% in the fourth quarter, up from negative 28% in the first quarter.

This year looks even better. PayPal plans to cut an additional $1.6 billion in expenses, and management is forecasting non-GAAP earnings growth of 18% in 2023. Of course, consumer spending will likely remain muted until inflation cools, meaning investors should expect weak revenue growth in the coming quarters. But PayPal is well-positioned to reaccelerate its top-line momentum in a more favorable economic environment.

The long-term investment thesis is straightforward: Digital payments are replacing cash transactions both online and offline, driven by the growing popularity of e-commerce and mobile wallets, and PayPal is perfectly positioned to benefit from those trends. It is the most accepted digital wallet in North America and Europe, and it was the second-most-downloaded finance app worldwide last year. According to Statista, PayPal is also the leader in online payment processing, with 42% market share.

Additionally, PayPal recently partnered with Apple to bring the iPhone maker's Tap to Pay technology to PayPal and Venmo iOS apps. That partnership will evolve this year, as U.S. consumers will soon be able to add PayPal- and Venmo-branded credit and debit cards to their Apple Wallets and use them anywhere Apple Pay is accepted. Those new features are especially noteworthy because Apple Pay is the most popular in-store mobile wallet among U.S. consumers, meaning the partnership positions PayPal to strengthen its position in physical retail.

Management estimates its addressable market at $110 trillion, but PayPal processed just $1.4 trillion last year, indicating the company has captured just 1.2% of its market opportunity. The stock currently trades at 3.2 times sales, near its cheapest valuation in the last five years. That creates a compelling buying opportunity for investors.