The bear market has sent many stocks to new lows. And in some cases, stocks are trading around levels that they haven't been at in years. Three stocks that are trading near their four-year lows that you may want to keep a close eye on right now are Illumina (ILMN -1.88%), PayPal Holdings (PYPL 1.39%), and Unilever (UL -0.12%). Are these stocks bargains worth picking up right now, or are they likely heading even lower? Let's see.

1. Illumina

Genomic-sequencing company Illumina has fallen 48% year to date while the S&P 500 has declined by just 17%. Trading at roughly $200, the stock is now around the levels it was at in 2017 and down an incredible 62% from its high of $526 that it hit last year.

Illumina is a promising growth stock with lots of potential in revolutionizing healthcare, by making it easier to run genetic tests and identify rare diseases that people may otherwise not notice until later on in life. Last year, the company reported that sales rose 40% to $4.5 billion,However, for 2022, Illumina projects a slower growth rate of between 14% and 16%.

Another headwind is that the European Union is proceeding with an antitrust review of the company's $8 billion acquisition of Grail, whose early detection cancer tests could provide another strong growth avenue for Illumina in the future (in 2021, Grail generated $12 million in sales). But it could take multiple years for that issue to get sorted out.

An additional hurdle for investors considering buying shares of Illumina today is that the stock trades at a forward price-to-earnings ratio of nearly 50. Although that's down from the multiple of 100 it was at earlier in the year, this is still a rich multiple to pay. As investors have been more wary of high-priced investments amid fears of a downturn, Illumina has been among the most beaten-up healthcare stocks this year.

The company, does, however, offer some attractive growth potential as the global genetic testing market could more than double by 2030 to a value of $36.1 billion, according to analysts from Straits Research. And the company's impressive profit margins are around 15%, suggesting that Illumina's bottom line (and, hence, the P/E) could improve significantly as the business expands. Buying it now could be a solid move -- but only if you're willing to buy and hold for years, as a recovery may not be imminent.

2. PayPal

Fintech stock PayPal has fallen even more sharply this year, down 57% in 2022. The stock has been rallying of late, but even at $80, this is around where it was for much of 2018. Although e-commerce isn't going anywhere but up in the long term, the company's growth has slowed down of late.

Through the first three months of this year, sales rose just 7% year over year to $6.5 billion and were down 6% from the previous quarter. A year earlier, the company's sales were up by a more impressive rate of 31%.

PayPal's forward P/E multiple of 21 is a lot more tenable than Illumina's. And financial stocks Visa and Mastercard trade at multiples of around 30, making PayPal look cheap by comparison. Although the business is slowing down amid a return to normal this year, it remains a great way to invest in e-commerce.

PayPal is a top name in the global payments industry and could be an excellent long-term buy at its reduced valuation.

3. Unilever

Consumer goods company Unilever is typically a stalwart. So even a 12% drop in value this year is surprising for the business. Its shares nosedived when investors learned about the Russian invasion of Ukraine earlier this year and, as the company noted, it would be halting exports and imports in Russia.

Inflation has also delivered another headwind for the business. However, on its most recent earnings report, the company noted that its underlying sales growth for 2022 would be close to 6.5%. Unilever has increased prices to help offset the impact of rising prices, and it notes that there has been an impact on its volumes. But with sales growth still rising steadily this year, the business looks sound despite all the adversity.

Unilever has 400 brands worldwide, including Dove, Ben & Jerry's, and Hellmann's. A global presence has made its business vulnerable to market conditions all over the world. But with popular products that remain in demand even amid inflation, Unilever is proving to be a resilient investment to own today. You have to go back to early 2017 to find the last time the stock was trading lower than it is now.

For long-term investors who are looking to buy the stock and take advantage of its 4% yield, now may be an opportune time to do so.