The first half of 2022 is now in the books, and it was a stinker. Food and gas prices skyrocketed; inflation rose to 40-year highs. And while the unemployment rate remained low, wage growth failed to keep pace with inflation, meaning many workers fell behind in real terms.

What's more, the stock market rolled over. The S&P 500 fell 20.6% in the first half of 2022, marking its worst start since 1970. The Nasdaq Composite dropped 29.5%; the Dow Jones Industrial Average sank 15.3%.

Yet all hope is not lost. The last six months were terrible; the next six might be stellar. 

Don't believe me? Consider 1970. As noted earlier, it was another year when the stock market got off to a rough start. The Dow fell 15.3% from January to June. But that same index rose 22% in the second half of 1970. And that was in the middle of a recession!

Remember, markets are cyclical. The smart thing to do is buy and hold, riding out the ups and downs. All the while, it's best to look for great companies with excellent business models and invest long-term. 

With that in mind, let's examine three growth stocks you can pick up on the cheap today and hold for a lifetime.

1. Alphabet

If you had invested $10,000 in Alphabet (GOOG -1.00%) (GOOGL -1.05%) back in 2014, you'd have more than $39,000 today. And that's with the stock down 23% from its all-time high, achieved last year.

Alphabet, the parent company of Google, is an absolute giant. It generated over $54 billion of ad revenue in the first quarter of 2022 alone. 

And how does it make so much money, you might ask? Well, the bulk of that money comes from Google Search, the company's ubiquitous internet search engine. Whether you're on a smartphone, computer, or tablet, chances are it has a Google Search feature. So when you require a plumber, a mechanic, or a lawyer, Google is there with the links you need. And some of those links are paid ads.

Alphabet is due to report second-quarter earnings on July 26, and analysts expect it to record over $70 billion of revenue, up 13.9% year-over-year. With Alphabet shares down 19.5% year to date, now seems like a great time to pick up this growth giant on the cheap.

2. Airbnb

The second growth stock I want to buy on the dip is Airbnb (ABNB -3.66%). This leisure-tech name combines a long-term secular growth story with a broader "reopening" trend. 

The long-term secular growth trend involves how, where, and why people are traveling. It turns out that many people -- particularly young people -- no longer view travel as a weekend getaway from the day-to-day grind. Instead, they view steady travel as a key ingredient in their life. They're traveling farther, staying longer, and more or less living life "on the road." 

That's great news for a company like Airbnb. In its most recent quarter, Airbnb CEO Brian Chesky noted that long-term stays (28 days or more) grew to 21% of gross nights booked. If you include stays of seven days or more, that figure grows to 48%. In short, Airbnb isn't just a vacation company; it's a landlord -- minus the overhead.

As for the reopening trend, we can all appreciate that this summer feels different. Airports are full for the first time in years; beaches are packed. With millions of tourists returning to traveling, Airbnb is poised to benefit. 

The company reported $1.5 billion of revenue in the first quarter of 2022, and analysts expect $2.1 billion when the company reports second-quarter earnings in mid-August. The summer-heavy third quarter should be even better, with Wall Street expecting revenue of $2.8 billion for Airbnb. That's the sort of growth that shouldn't be ignored, yet shares of Airbnb are down 42% year to date. 

I'm not waiting for the market to notice; I'm happy to continue buying Airbnb while it's on sale.

3. Roblox 

My third pick is Roblox (RBLX -2.27%). This metaverse-themed game platform came to prominence during the pandemic, as school-aged children looked for ways to connect with friends online. 

Shares were clobbered to start the year, falling almost 78% in less than five months, as the market hammered anything with the "stay-at-home" angle. Yet, if you dig under the surface even a little bit, it's clear that Roblox isn't just a "stay-at-home" stock. 

Key metrics, like daily active users (DAUs) and hours engaged, have increased over the last 12 months, even as pandemic restrictions have waned and kids have returned to school. 

And Wall Street is coming around on Roblox. Analysts expect 2022 revenue of $2.8 billion, up from $1.9 billion last year. What's more, of the 21 analysts covering Roblox, only one has an underperform/sell rating on the stock, while 13 rate it as a buy or strong buy.

With over 54.1 million DAUs, Roblox already has a solid base of users. I fully expect the company to more effectively monetize its platform as it ramps up ad integration. In the meantime, I'm happy to accumulate shares now, as the stock still licks its wounds from a tough start to 2022.