These are volatile times for investors.

A whiff of good news is sending some stocks off to stratospheric heights, but even a modest stumble can send other stocks crashing.

I've been singling out attractive opportunities in low-priced stocks since my original "5 Stocks Under $10" column 10 years ago, and I'll have another installment in that monthly column in two weeks. However, going over the Friday close of so many well-known companies and former market darlings I figured I'd point out a handful of stocks that have surprisingly cratered to the point that they're trading in the single digits.

Let's go over a few of the surprising names.

Groupon (Nasdaq: GRPN) -- $9.97
The obvious joke that everyone's been dying to make is official: Groupon is finally available at 50% off its original price.

The daily deals leader went public in November at $20. The shares quickly traded above $30, as investors set aside concerns about the unprofitable business model and SEC objections with Groupon's funky accounting metrics.

Things haven't gone well for Groupon. Just last month, the dot-com disappointment warned that it would be restating its financials for the holiday quarter because of the need to increase its loss reserves on refunds.

The good news here is that Groupon is now trading at just 13 times next year's projected profit of $0.75 a share. Given the tenuous nature of the business, it's obviously not a lock to earn that much next year.

E*TRADE (Nasdaq: ETFC) -- $9.98
When the discount broker issued a 1-for-10 reverse stock split -- catapulting its shares into the teens -- it seemed as if E*TRADE was kissing its days in the single digits goodbye.

No such luck.

The stock is back below $10, and it doesn't seem fair. E*TRADE has come a long way. It was the only discounter to post better-than-expected results this past quarter. Its loan portfolio is still problematic, but that situation has improved over time.

Zynga (Nasdaq: ZNGA) -- $8.33
We're now just days away from Facebook's IPO, and the best sympathy play is a busted IPO.

The leading social gaming company may have gone public at $10 five months ago, but it quickly shot higher.

Financially speaking, Zynga is holding up well. It topped analyst revenue and profit targets in its most recent quarter. After a year-end Facebook filing showed that Zynga accounted for 12% of the social networking giant's revenue, an updated report revealed that Zynga now accounts for 15% of Facebook's revenue through the first three months of the year.

The rub is that investors have tired of the fickle nature of social gamers. Zynga's had to acquire some of its most popular games as its earlier releases grow stale. Can a single company stay on top forever in a niche that's deep-fried in flux?

Logitech (Nasdaq: LOGI) -- $9.85
Thinking inside the box paid off for Logitech until recently. As long as PC sales were booming, computer and laptop buyers would turn to Logitech for keyboards, optical mouse controllers, and webcams.

The market for third-party accessories has been harder to justify these days. PC sales have been stagnant. Tablets, smartphones, and many laptops have built-in cameras that shoot decent snapshots and video.

Pandora (Nasdaq: P) -- $8.75
The music discovery website may have been dismissed by many as a profitless dot-com speedster when it went public last year, but then Pandora rattled off back-to-back quarters of profitability in its first two reports as a public company.

Pandora slipped back into the red in its most recent quarter, but growth is still booming.

The problem at Pandora is that business may be slowing. The stock got clobbered two months ago after Pandora issued a lukewarm outlook calling for a sequential dip in revenue and a wider deficit than analysts were targeting for all of 2012.

Satellite radio and even terrestrial radio apps are starting to close the gap with Pandora in terms of seamless music discovery, so Pandora has plenty to prove if it wants to reverse its disappointing guidance.

Five for the road
These five stocks aren't trading in the single digits by accident. Some will find their way back into the double digits soon. Others will drift lower until they are forgotten penny stocks.

Finding promising stocks while they're still cutting their baby teeth is at the heart of the Rule Breakers newsletter that I write for. You can check it out for free this month with a 30-day trial subscription. There are roughly a half-dozen active stock recommendations in the growth stock research service trading for less than $10 at the moment. Check those out, and I'll be back with this month's pick of single-priced stocks worth buying on the third Monday of next month.

If you enjoy low-priced stocks because they have the potential to generate huge gains, you'll want to read about the next Rule-Breaking multi-bagger. The report's free, so it's even cheaper than some of these stocks. Check it out now.