Pet rocks. Eight-track tapes. Growth stocks. One of the three doesn't belong.

Sure, some might think that the time for investing in growth stocks is over with the huge sell-off in recent months. A transition from riskier assets into more stable assets has been underway for a while now.

But these cycles come and go. For those with a long-term outlook, investing in assets when they're out of favor can pay off handsomely. Growth stocks might not be highly prized now, but it's only a matter of time before they once again shine like stars.

Some alternatives are better than others, though. Here are three growth stocks to buy with $1,000 right now.

A person looking at stock charts on a laptop PC.

Image source: Getty Images.

1. Novocure

Novocure (NVCR -4.43%) isn't profitable. Its shares have plunged more than 60% below the high set last summer. The company's growth has fizzled to boot. Revenue slid 7% year over year in the fourth quarter of 2021. And Novocure projects active patient growth of only 2% to 5% this year.

You might think I'm trying to talk you out of considering this healthcare stock, but I'm really not. However, I didn't want to sweep Novocure's negatives under the rug. The reality, though, is that the company is potentially approaching a huge tipping point that many investors are overlooking.

Novocure's Tumor Treating Fields (TTFields) use electrical fields to disrupt cancer cell division. The therapy has already been approved for treating glioblastoma (an aggressive form of brain cancer) and mesothelioma (cancer resulting from exposure to asbestos).

Novocure expects to report results from a pivotal study targeting non-small cell lung cancer this year, with results from late-stage studies in ovarian cancer and brain metastases on the way in 2023. It also should announce data from a pivotal study of TTFields in pancreatic cancer in 2024. 

There's no guarantee that TTFields will win regulatory approvals in all three indications. However, Novocure's chances appear to be pretty good. Importantly, these additional types of cancer represent a market opportunity that's 14x bigger than the company's current market. With just a little bit of luck, this stock could skyrocket over the next few years.

2. PayPal Holdings

COVID-19 provided a huge tailwind for PayPal Holdings (PYPL 0.25%) in 2020 and much of 2021. However, the digital payments giant has given up nearly all of its pandemic-era gains. As is the case with Novocure, PayPal stock has fallen more than 60% from its peak last summer.

What's behind PayPal's steep plunge? The company's loss of eBay's business played a big role. So did PayPal's guidance for lower user growth. 

However, the company continues to generate strong growth, excluding eBay. PayPal is also changing its strategy to focus more on increasing revenue per user than on boosting customer counts. This appears to be a smart move over the long term. 

PayPal's online digital payments will almost certainly increase as e-commerce market penetration rates rise. The company's efforts to implement QR code functionality in stores to support in-person digital payments should pay off over time. PayPal also has tremendous opportunities to further monetize Venmo. This fintech stock looks like a relative bargain at its current valuation.

3. MongoDB

The sell-off in growth stocks hasn't hit MongoDB (MDB 0.89%) as hard as it has many others. Still, though, the database developer's shares are down close to 30% from their highs a few months ago.

But MongoDB's business continues to fire on all cylinders. The company blew away expectations with its fourth-quarter results. Revenue soared 56% year over year. Much of that growth was driven by Atlas, MongoDB's cloud-based database management system.

There's been even more good news since MongoDB's Q4 update. On March 15, the company announced that it's expanding its collaboration with Amazon Web Services (AWS). The six-year agreement will facilitate the partners working closely on accelerating the shift of customer workloads to the cloud using Atlas on AWS. 

Mike Gordon, MongoDB's COO and CFO, stated in the company's Q4 call, "We remain convinced that we're in the early innings of pursuing our large market opportunity." I think this take is spot on. MongoDB is an ideal growth stock to buy on the current pullback and hold for the long term.