Just as we examine companies each week that may be rising past their fair value, we can also find companies potentially trading at a bargain price. While many investors would rather have nothing to do with companies tipping the scales at 52-week lows, I think it makes a lot of sense to determine whether the market has overreacted to the downside, just as we often do to the upside.

Here's a look at three fallen angels trading near their 52-week lows that could be worth buying.

Primo-donna
All that's fizzy is not bubbly. Just ask shareholders of Primo Water (Nasdaq: PRMW), which have been drowned for an 80% drop in the company's stock since early August. Seen as a prime competitor to SodaStream (Nasdaq: SODA) in the home sparkling beverage business, Primo has had two consecutive quarterly setbacks for its most anticipated product, FlavorStation. Despite this, the positives continue to outweigh the negatives, and the company could be looking like a Primo-donna in no time.

For the quarter, sales rose by 121%, with water segment sales, which account for 70% of the company's revenue, jumping 124%. Primo's fourth-quarter guidance remains upbeat, with the company anticipating that water dispenser sales will rise by 80% and water segment sales by 50%. Still, investors have a hard time looking past the FlavorStation debacle. Let me tell you, folks, Primo is much more than FlavorStation. FlavorStation is simply the gravy on top of the meat and potatoes of this company. Now that it's at 50% of book value and 11 times forward earnings, consider me highly intrigued with Primo's prospects.

You may not know them now...
You may not be familiar with Sun Life Financial (NYSE: SLF) now, but as the commercial says, someday you will. The Canadian-based life insurance and annuity provider blew Wall Street estimates out of the water nearly three weeks ago. The only problem -- it was in the wrong direction. Sun Life reported a whopping $572 million operating loss, significantly worse than anyone on Wall Street had predicted. Even worse, the company is changing the way it values its variable annuities and segregated fund insurance contract liabilities, which could translate into a $550 million to $650 million loss in the fourth quarter. Still, buying in when things are at their worst could be for the best.

Sun Life runs one of the most conservative investment portfolios among insurers and was exposed to a perfect storm of falling interest rates and very volatile markets in the third quarter. It's very unlikely that volatility will remain as high as it has been, and its fourth-quarter charge is clearly a one-time event. Consensus estimates for 2012 currently place Sun Life at only seven times forward earnings. With a dividend yield of more than 7%, it triples the current yields of MetLife (NYSE: MET) and China Life Insurance (NYSE: LFC).

Wall Street's flub
I'm not sure if Wall Street was looking at the same earnings report I was looking at, but RadiSys (Nasdaq: RSYS) seems to have unfairly picked the short stick.

The application-ready software and hardware provider reported a 30% jump in sales and a 27% jump in net income. Where RadiSys really took its drubbing was based on its guidance. Still, the company's forecast looks great to me. In 2012, RadiSys is forecasting revenue of $345 million to $355 million, and non-GAAP profits of $0.80 to $0.85, both of which are consistent with previous guidance. Even gross margin is expected to improve to a range of 36% to 37%. Based on RadiSys' forecast, the company is trading at less than six times forward earnings . Undervalued much? I think so.

Foolish roundup
Investors seemed to have overlooked either a long history of growth or fast growth on the horizon in favor of drubbing these stocks over one or two bad reports. All the better, these three companies look as cheap as they've been in a long time.

What's your take? Do these fallen angels deserve a second chance? Share your thoughts in the comments section below and consider adding Primo Water, Sun Life Financial, and RadiSys to your free and personalized watchlist to keep up on the latest news with each company.