Cassius Marsh Pittsburgh Steelers
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Pittsburgh Steelers linebacker Cassius Marsh has had a passion for trading cards most of his life. When he was growing up, he was first interested in Pokemon and Yu-Gi-Oh! cards. As a kid, the Steelers linebacker was playing card games or shopping for more items to add to his collection whenever he wasn't on the football field. 

Once Marsh discovered Magic: The Gathering, that quickly became his ultimate passion.

"I went into a shop in my hometown that's still there. I went in and was looking for Yu-Gi-Oh! or Pokemon because that's what I was really into," Marsh told CBS Sports. "They didn't have either, but they had Magic: The Gathering. I didn't know what it was. Lucky for me, there were two guys that were there playing the game at the time on a table. So I sat down and watched them play until my mom came to get me. I bought 11 cards that day with the money my mom gave me. I've been hooked ever since."

Years later, Marsh's card obsession has turned into a business.

In February, Marsh and his business manager, Nick Nugwynne, opened Cash Cards Unlimited in Marsh's hometown of Westlake Village, Calif.

"I had been thinking about it for a long time. Originally, it was just because I loved to hang out at the card shop all day and it's always something I've enjoyed," Marsh said. "Then I started to evaluate all the trading card shops that I've been to. The majority of them are pretty dirty and they don't put a lot into the presentation of their shop. It's not like walking into a Louis Vuitton store, I'll say that. That's kind of my thought process was with opening a shop. I want to create that type of experience for Magic: The Gathering players and card collectors. Trading card shops up until recently are not a place where you'd take your girlfriend."

Cash Cards Unlimited is a shop that buys, sells and trades cards. The shop also has a partnership with TCGPlayer.com and sells cards through the company. In addition, Cash Cards Unlimited sells cards on their own website and has a partnership with a grading company that allows patrons to get their cards professionally graded.

With the NFL currently in the offseason, Marsh spends the majority of his time at Cash Cards Unlimited when he isn't training. After Marsh finishes his morning workouts, he comes straight to the card shop and puts the "same energy, focus, and professionalism" into the business as he does to being an NFL player.

The business has been very successful, despite only being open for two months. Earlier this month, Marsh and New York Giants linebacker Blake Martinez participated in a huge Pokemon card pack break that was aired on the shop's Instagram account

Like the way he turned his love of cards into a massive part of his life, Marsh did the same with football. He was very successful on the gridiron at an early age and was one of the top defensive tackle recruits in the country when he starred at Oaks Christian School in Westlake Village. According to 247 Sports Composite rankings, Marsh was rated as a four-star recruit in the 2010 class and the 11th-best defensive tackle in that class. As far as defensive tackles go, Marsh was rated ahead of players like Los Angeles Rams star Aaron Donald and Johnathan Hankins of the Las Vegas Raiders.

Marsh's passion for the card industry is on display every day he is in his shop. In his experience so far, his favorite part of owning his own business has been the interaction that he has with younger generations.

"I think the best part is seeing young kids' reactions when they pull dope stuff. It's sick, it's just so pure," Marsh added. "The reactions from adults and teenagers is cool, but kids from 10-13 get so hyped. Their parents buy them some Pokemon and they shed tears. That stuff is really cool to see how much those kids care and how much it means to them. The other part I really enjoy is when people bring in their collections and I just get to go through these amazing collections. Whether I end up buying them or not, it's still an amazing experience. I get to see the coolest cards that are out there day in and day out."

Marsh being impressed by someone else's collection is surprising, seeing how he has some quite impressive -- and expensive -- cards of his own. While he hasn't physically priced out his collection, Marsh believes that his collection could be worth somewhere in the neighborhood of $250,000. 

"I've been saying $250,000 for a while," Marsh said. "I've priced out two decks and together they were $50,000. I have like 30 decks and a bunch of binders of rare stuff. I'm not sure exactly what my collection is worth, but I'd say minimum $250,000. I've said that before and I'm sticking with that number."