After being laid off, this 35-year-old founded NerdWallet with $800 — now it’s worth $500 million

Today, Tim Chen is CEO and co-founder of personal finance website NerdWallet, which sees 10 million monthly visitors and is valued at more than $500 million.

But in 2008, like so many others during the financial crisis, Chen found himself unemployed.

After spending four years working at hedge funds like Perry Capital and JAT Capital Management, he found out "basically on Christmas Day," that he was being laid off, Chen tells CNBC Make It.

"It was super devastating, because I'd just been very achievement-oriented my whole life and I was very concerned with external status and all that stuff," says Chen, who graduated from Stanford.

Now though, Chen sees it as one of the best things to ever happen to him. It turned him into a successful entrepreneur.

"I always dreamed of doing something entrepreneurial. I just never felt like I had the permission to," he says.

Stumbling onto an idea

Chen, 35, says he got the idea for NerdWallet "sitting around twiddling my thumbs," while out of work.

He had received an email from his sister, who was living in Australia, with a question about finding a credit card with lower foreign transaction fees.

"My first inclination was, 'Let me Google that for you and I'll get back to you in three minutes,' Chen says. "And, I was shocked I couldn't find anything on Google that wasn't basically marketing [or] promotional material."

Chen says he drew on his own finance experience and still it took him, a professional, a week of extensive research to compile what several major banks and credit card companies had to offer. He sent his sister an Excel spreadsheet breaking down her options.

Soon, that spreadsheet was being forwarded around widely outside of his own group of family and friends.

It made Chen realize there was "real shopability problem in financial services," where consumers often had to sift through banks' dense materials for information. Without a professional financial advisor, it's hard to compare products. Meanwhile, "Your checking account provider might give you a mortgage, a credit card, an auto loan, eventually insurance or wealth management services, and they'll make something like $50,000 off of you over the course of your life," Chen says.

"That's how the whole system works."

Chen wanted to offer more transparency with online financial services advice. So working out of his Manhattan apartment, he used $800 of his own money to cover start-up costs like web hosting and domain fees and software and started NerdWallet.

The plan was to provide pros and cons of various financial services and to answer questions, provide advice and aid people making financial decisions via articles written by professional personal finance journalists.