Now would be a great moment to add a few growth stocks to your portfolio. Why? Because we're heading toward a bull market, and that type of economic environment tends to favor these sorts of players. We're not there yet, but, since historically, every U.S. market correction or bear has eventually been followed by a bull, there's reason to be optimistic about the future in this case. And smart investments now could lead to big rewards later.

Speaking of smart buys, today, you can pick up some top growth stocks for reasonable prices -- and two in particular would make no-brainer additions to any growth portfolio. I'm talking about trillion-dollar companies that dominate their markets and have posted triple-digit percentage revenue and stock price gains over the past decade: Apple (AAPL -0.50%) and Amazon (AMZN 1.04%). Their growth stories are far from over, and they could truly take off in an economic environment that favors expansion.

Apple

Apple has won over the world with practical yet innovative products such as iPhones and Apple Watches. The company's brand strength offers it both pricing power (the ability to raise prices without losing customers) and a significant moat (i.e., a competitive advantage).

The bottom line is most Apple fans love its products so much that they'll pay a premium for them -- and generally aren't tempted to switch to another brand. In 2023, for the second straight year, Apple topped consulting company Kantar's list of most valuable global brands.

But even when a tough economic environment puts a brake on consumer discretionary spending, and therefore puts pressure on sales of Apple products, the company still can win. That's because it also sells a wide variety of services -- from iCloud data storage to digital content. In its fiscal third quarter, thanks to more than one billion paid subscriptions, the company's services revenue reached a record high.

Over time, Apple has increased its net income and other important measures. For example, growth in return on invested capital shows Apple has used its cash wisely -- and is benefiting from its investments.

AAPL Revenue (Annual) Chart

AAPL Revenue (Annual) data by YCharts.

And consider its valuation. Even after the stock gained more than 35% this year, recovering from its 2022 slide, it still trades for only 27 times forward earnings estimates. That looks like an absolute steal for a company with Apple's track record, competitive advantages, and prospects.

Amazon

Amazon is a leader in two markets that are growing at double-digit percentage rates -- e-commerce and cloud computing -- and there's reason to believe the company can maintain its dominance in both. In e-commerce, the youngest generation of shoppers favors Amazon, which bodes well for its revenues down the road. More than half of teens in Piper Sandler's latest teen survey say Amazon is their favorite shopping website.

And to keep customers happy, Amazon continues to make its deliveries faster. That's an important point because Amazon has noted customers are more likely to order an item if estimated delivery times are speedy.

As for cloud computing, Amazon Web Services (AWS) has maintained global leadership for years. This is key because AWS generally drives profits at Amazon.

Amazon also has demonstrated its ability to manage during tough times. Last year, Amazon reported its first annual loss in almost a decade as economic headwinds weighed on the business. But Amazon quickly and efficiently turned things around, revamping its cost structure and pouring investment into high-growth areas such as technology infrastructure.

As a result, the company reported a doubling of operating income in the most recent quarter, and it switched to an inflow of cash versus an outflow in the year-earlier period.

Considering Amazon's strengths in two high-growth markets, its valuation of 61 times forward earnings estimates wouldn't scare me away. This company has what it takes to continue thriving -- especially in the next bull market.