The best time for value investors to buy stocks is in a market panic. With the Dow Jones losing just under one-third of its market value this past month due to the COVID-19 pandemic, a number of otherwise healthy companies have been caught in the crosshairs of this sell-off.

This means that many high-quality stocks that normally would be trading at pricier valuations are now dirt cheap. Here are three stocks you should consider adding to your portfolio due to how cheap they've become.

An investor pushing a shopping cart filled with good deals.

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1. Newmont

Gold has always been seen as a place to store value when the markets get dicey. As such, prices for the precious metal tend to move in the opposite direction of the market. While the current market decline is good for investors who own gold, it's also great for gold mining companies whose profit margins expand significantly when gold prices jump.

Newmont (NEM 12.46%), formally known as Newmont-Goldcorp, is not only one of the largest gold mining companies in the world, but it's surprisingly cheap as well. Newmont trades at a 3.1 price-to-sales ratio (P/S), with a price-to-equity ratio of 11.7.

In addition to Newmont's size, the company has a number of things going for it. For one, Newmont has one of the most impressive gold mineral reserves on the planet. By the end of 2019, the company confirmed it held just over 100.2 million ounces in reserves across its various mining projects. This is up 53% from the 65.4 million ounces reported one year prior.

Secondly, the gold miner has promised to reward shareholders with a substantially increased dividend. Earlier this year, the company said it would increase its quarterly dividend by 79% from $0.14 to $0.25 per share as of April.

With Newmont's management saying that it could sustain its current rate of production -- around six million ounces per year -- for decades to come, there's a lot of stability in this gold miner. If COVID-19 continues to get worse as the markets continue to decline, this could be the catalyst needed to send gold prices to record highs. In turn, the relatively cheap Newmont could become a big winner in such a market.

2. Bristol Myers Squibb

While some healthcare stocks have done well in the coronavirus bear market, many others have seen significant declines. Bristol Myers Squibb (BMY -8.51%) is one of them, with its stock having been on a steady decline for the past month. Currently, Bristol trades at just 3.2 times its P/S ratio, while offering a strong 3.7% dividend yield.

While there are other pharmaceutical stocks that are also trading cheaply with strong dividends, Bristol Myers stands out for its impressive margins and a strong growth record. Between 2018 and 2019, the company reported a 15.4% increase in year-over-year revenue. That's an impressive achievement for a company that's worth almost $110 billion.

Thanks to Bristol's acquisition of Celgene last year, the company's pipeline is looking more promising than ever. This includes Bristol's existing lineup of blockbuster drugs, such as its cancer drug Opdivo and its blood clot treatment Eliquis, which brought in $1.8 billion and $2.0 billion, respectively, in quarterly revenue. Many of Bristol's drugs are witnessing stellar revenue growth as well, with Eliquis reporting a 19% increase in sales from last year.

There are a number of promising new drugs it added with the Celgene acquisition as well, most notably Revlimid. This drug -- which is used in treating multiple myeloma, a type of bone marrow cancer -- has already brought in $1.3 billion in revenue between Nov. 30 and Dec. 31. That's an impressive figure for just a month's worth of sales, and could easily become Bristol's new top-selling treatment once next quarter's results are announced.

It's rare for a company to have such great growth potential and be so affordably priced. That's why Bristol is a steal of a deal right now.

Three rolls of tobacco.

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3. Altria

The tobacco industry has definitely faced some challenges, and it's not surprising that many investors might not want to touch this sector. However, if you're open to the idea of owning a vice stock, this tobacco company could very well be a diamond in the rough.

With Altria's (MO 1.45%) stock price having seen significant declines over the past month due to the COVID-19 epidemic, Altria's already strong dividend yield looks even more appealing. Currently, the company's dividend is at 9%.

While this might not be enough to make up for a decline in product sales over the past few years, Altria has historically had success in increasing the prices of its products to make up for declining purchases. While this would have an adverse effect on a normal company, the addictive nature of nicotine means that frequent smokers aren't as likely to be put off by a 5% or 10% increase in price, especially for their favorite brands. Altria has also been diversifying its business into other areas as well. This includes e-vaping products and alcohol, as well as cannabis via a significant investment in the Cronos Group.

The company's P/S ratio is currently at 3.2, the lowest it's been in years. Altria also has had a history of buying back its own shares to raise prices for shareholders, and it wouldn't be surprising for investors to see something similar happen in the near future as management considers bolstering the company's declining stock price. Between 2015 and 2019, Altria returned over $32 billion in cash to shareholders from dividend payments (which have been consistently increasing) as well as share repurchases.

While some investors might find it a little distasteful to invest in a tobacco stock, I'd be remiss not to point out Altria as a strong investment candidate in this current market climate.