This year, the S&P 500 dropped into its 22nd bear market of the last century, and the broad-based index is currently 18% off its high. That downturn has erased trillions of dollars, but it has also created some fantastic buying opportunities for patient investors.

Bear markets come in different shapes and sizes, but they have all ended the same way: a bull market rally. That means the next bull market is almost certainly on its way. In the meantime, must-own growth stocks Cloudflare (NYSE: NET) and MercadoLibre (NASDAQ: MELI) are trading at attractive valuations, and investors should jump on that buying opportunity.

1. Cloudflare: The fastest developer platform in the world

Software, cloud services, and websites must be fast, reliable, and secure to ensure a good user experience. Cloudflare makes that possible. Its global cloud platform accelerates and protects business-critical applications and networks while enabling customers to forgo complicated and costly on-premise hardware.

Cloudflare benefits from a tremendous scale. Its platform interconnects with every major internet service provider, cloud provider, and enterprise, making it one of the fastest networks in the world. Better yet, the company also operates the fastest developer platform on the planet, Cloudflare Workers. Not surprisingly, Cloudflare is the market leader in content delivery network software, according to research company G2, and Cloudflare Workers is the leading edge development platform, according to Forrester Research.

Growing brand authority, coupled with a freemium pricing model, has enabled Cloudflare to implement a very effective land-and-expand growth strategy. Its customer count jumped 18% to 156,000 in the third quarter, and the average customer spent 24% more over the past year. In turn, third-quarter revenue soared 47% to $254 million, and the company generated positive cash from operations of $43 million, up from a loss of $7 million last year.

Going forward, investors have good reason to be bullish. Cloudflare is also positioning itself as a key player in zero-trust network security. Its Cloudflare One product is a secure access service edge (SASE) that quickly and safely connects users to the web, cloud services, and private applications from any device or location. According to research company Gartner, 80% of enterprises will adopt SASE architecture by 2025, up from 20% in 2021. That tailwind puts Cloudflare in a great spot to create value for shareholders.

With that in mind, management estimates its addressable market will reach $125 billion in 2023, leaving a long runway for growth. And with shares trading at 16.2 times sales -- an absolute bargain compared to the three-year average of 41.7 times sales -- investors should buy a few shares of this must-own stock before the end of 2023.

2. MercadoLibre: The leading e-commerce and fintech ecosystem in Latin America

MercadoLibre operates the largest online commerce and payments platform in Latin America, which is one of the fastest-growing regions of the world in terms of internet penetration. That positions MercadoLibre to grow its commerce and fintech businesses quickly in the coming years. Better yet, the company has reinforced its leadership position with an array of value-added services that make its platforms even more compelling to merchants and consumers.

Specifically, MercadoLibre provides solutions for logistics, financing, and digital advertising, all of which help merchants grow their businesses. It also provides credit cards, loans, and digital wallet services to consumers. Those products make its commerce and fintech platforms stickier, supercharging the network effects inherent to its business model.

In the third quarter, MercadoLibre's fintech business reported 146% growth in its credit portfolio and 54% growth in total payment volume (TPV), while its commerce business reported 20% growth in gross merchandise volume (GMV). Putting the pieces together, total revenue soared 45% to $2.7 billion  in the third quarter, and generally accepted accounting principles (GAAP) earnings climbed 33% to $2.59 per diluted share. Those results are particularly impressive given the unfavorable foreign exchange rates the company is currently battling. For instance, operating income soared 116% during the quarter in constant currency.

Looking ahead, MercadoLibre has plenty of room to expand its business, and investors should expect its momentum to continue as growing internet penetration drives the adoption of e-commerce and digital payments in Latin America. For instance, e-commerce volume across all relevant geographies will total $291 billion by 2027, according to Statista, but MercadoLibre reported GMV of just $28.4 billion last year. Similarly, digital payment volume across all relevant geographies will total $511 billion by 2027, but MercadoLibre reported TPV of just $77.4 billion last year. That illustrates the monumental size of its market opportunity.

On that note, shares currently trade at a bargain valuation of 4.4 times sales -- far cheaper than the three-year average of 13.1 times sales -- creating an excellent opportunity for patient investors to buy this supercharged growth stock.