Buying stocks in a bear market can lead to significant returns in the long run. Even if you only have $500 to invest, you can focus on growth stocks with lots of potential and where you can make the most of your money. And over time, you can add to your position so that cumulatively you have much more skin in the game, leading to higher potential profits down the road.

A couple of stocks that may be a good fit for a $500 investment right now include CRISPR Therapeutics (CRSP -1.62%) and Roku (ROKU -0.19%). Here's why these stocks could deliver some sky-high returns.

1. CRISPR Therapeutics

CRISPR is a bit of a risky stock given that it isn't profitable right now, and a lot hinges on it obtaining regulatory approval on its gene-editing therapy, exa-cel, which the company has been working on with Vertex Pharmaceuticals. Exa-cel can help an estimated 32,000 patients with beta-thalassemia and sickle cell disease, which are rare blood disorders. It could be a multibillion-dollar opportunity, and the two companies are planning to submit regulatory filings before the end of the year.

If the Food and Drug Administration approves exa-cel, it will make CRISPR a safer investment, giving it a product that it can rely on to help grow its business (under its agreement with Vertex, CRISPR will share in 40% of any profits from exa-cel). Through the first six months of 2022, CRISPR has generated $1.1 million in collaboration revenue and grants. That pales in comparison to the $360 million in operating expenses it incurred during that time frame.

Regulatory approval of exa-cel, should it happen, could instantly send shares of the stock skyrocketing as it would give investors a growth catalyst to rally behind. Shares of CRISPR are down 43% from their 52-week high of $110.01. Plus, it would lead to better financials for the business in the long run, making it a more tenable investment option for risk-averse investors. And there's also the potential that it will become an attractive acquisition target for a larger healthcare company, which could also lead to a higher share price.

For now, CRISPR remains a risky stock because if the approval doesn't come through, it could result in significant losses for investors. This is where investing just $500 initially in it might make sense so that you don't put too much money at risk.

2. Roku

One stock that has already been involved in acquisition rumors is Roku. The company is known for its portable streaming sticks, which make it easy for anyone to turn a regular TV into a smart TV. Consumers can also buy TVs that already include Roku's streaming platform without the need for any extra hardware.

Earlier this year, there were rumors that streaming giant Netflix was looking into buying Roku, although nothing has come as a result of that. A move like that could make sense as it would give Netflix an easy way to diversify into hardware that would complement its existing service.

One reason Roku may be a good acquisition for a streaming business is that its shares have crashed 74% this year. The company's growth rate has been slowing down due to softness in ad spend, as companies have been scaling back on expenditures amid rising inflation. Like Netflix, Roku was a popular stock to buy amid lockdowns as streaming stocks looked like red-hot buys. But in the second quarter of this year (period ended June 30), Roku incurred an operating loss of $110.5 million, which was its second straight period in the red. And net revenue of $764.4 million rose by 18% (versus 81% growth a year earlier).

Roku's business has slowed down, but the company still has more room to get bigger as advertisers come back and consumers look to shrink their bills and ditch cable; Roku has a free channel that provides a variety of content. And the platform itself can be a convenient hub that makes it easy to juggle multiple streaming services. Its operating system remains the top seller in the U.S. smart-TV market, suggesting that consumers do see value in the platform.

As is the case with CRISPR, there's some risk with Roku as its business is not profitable, and a lot will depend on its growth numbers moving forward. But that's in the short term. When looking at the longer term, whether it's due to an acquisition or the sheer growth potential in the video streaming market, which analysts at Fortune Business Insights project will grow at a compound annual growth rate of nearly 20% until 2029, Roku is a stock that I'm confident has the potential to deliver some fantastic returns for investors.