They say that big things come in small packages, and sometimes the same can be said about stock prices. There are plenty of stocks trading in the single digits, and while most of them -- let's face it -- are there for a reason, risk-tolerant investors can sometimes find some real gems among low-priced equities. 

Sirius XM Holdings (SIRI -0.72%)Glu Mobile (GLUU), Fitbit (FIT), GoPro (GPRO -2.26%)Zynga (ZNGA), Rite Aid (RAD), and Groupon (GRPN -3.12%) are some of the big names with low prices that I'm watching these days. Let's take a closer look at these seven stocks trading for $7 or less. 

Katy Perry at a Sirius XM Radio town hall.

Image source: Sirius XM Holdings.

1. Sirius XM Holdings -- $6.94

Not every stock trading in the single digits is a loser. Sirius XM stock has been a nearly 140-bagger since bottoming out at a nickel in 2009. The satellite radio provider has been a beast over the years. The shares are trading higher for the 10th year in a row. 

Slow yet steady growth and consistent profitability have won over the skeptics. Despite the proliferation of smartphone apps, connected cars, and carless millennials, the number of satellite radio subscribers keeps growing. 

2. Glu Mobile -- $6.94

Another hot stock that's on the verge of cracking through the $7 ceiling is Glu Mobile. The mobile app publisher that has made waves in the past with titles including Kim Kardashian: Hollywood and Cooking Dash has an even bigger hit on its hands these days with Design Home, an interior decorating simulator.

The unlikely hit is accounting for 38% of Glu Mobile's bookings these days. Design Home has also led the app developer to boost its guidance with every passing quarter. The stock has more than tripled since the start of last year. 

3. Fitbit -- $6.08

Fitbit has had a rough couple of years as consumers trade in their wrist-hugging fitness trackers for smartwatches and smartphones that monitor activity levels. Revenue declined 15% in Fitbit's latest quarter, and its quarterly deficit widened. 

Lost in the slide -- revenue has clocked in lower for seven consecutive quarters -- is that Fitbit is emerging as a strong smartwatch player. Smartwatch sales soared 55% in Fitbit's latest quarter, and that was with its new Fitbit Versa selling out. This turnaround won't be complete until sales declines and losses reverse themselves, but Fitbit could be sprucing up a second act here. 

4. GoPro -- $6.56

Folks aren't buying GoPro's namesake action cameras the way they used to, but investors who took a chance by buying into GoPro at its springtime lows are now sitting on a nearly 50% gain. Revenue stumbled just 5% year over year in its latest quarter, and the improvement was substantial sequentially. 

GoPro also posted a narrower loss than analysts were expecting, the second time in a row that we've seen that happen. Broadening its product offerings and shaving costs are helping, and GoPro expects to return to profitability next year.

5. Zynga -- $3.74

The company that once defined the casual and social gaming market with FarmVille, Mafia Wars, and Words With Friends is still making waves. Zynga turned heads on Tuesday after it landed a deal to breathe new life in the Star Wars franchise as a mobile gaming property. 

Zynga was already bouncing back before seeing what The Force can do. Revenue and mobile bookings inched higher in the second quarter, and it came through with double-digit percentage growth in mobile and daily active users. 

6. Rite Aid -- $1.44

The out-of-favor drugstore operator keeps getting jilted at the altar. Regulators blocked its plans to merge with a larger drugstore chain a year ago, and Rite Aid was hoping to rebound by hooking up with Albertsons, but retail and institutional investors nixed that hookup

Rite Aid shares have plummeted 22% in the two weeks since it called off the vote that it was going to lose for the combination with Albertsons. The partial asset sale that it had to settle for when its first proposal came undone has helped shore up its balance sheet, and the payoff could be substantial if Rite Aid finds a way to just survive in this cutthroat climate. 

7. Groupon -- $4.52

The daily deals leader may not seem to be at its best these days. Revenue just slipped for the 10th quarter in a row, but the top-line weakness has been partly by design. Groupon has backed out of profitless international markets and shifted away from low-margin merchandise sales. 

There's still a market for Groupon. It has 32.2 million active customers, and it continues to smoke out new initiatives to enhance its relationship with customers and local businesses hungry for leads. Groupon has time to get it right, as it's backed by a cash-rich and debt-free balance sheet. The deal maker is becoming the deal itself.