A mystery millionaire is hiding away cash in envelopes across San Francisco Bay Area for random people to find and keep for themselves.

The man under the Twitter handle @HiddenCash is posting clues about his "treasures" for whoever is interested to get it.

In a phone interview with ABC News, the mystery millionaire, who still chooses to keep his identity, said that he has plans of hiding away cash indefinitely and will expand to New York and Los Angeles soon. By Thursday night, he had already given away $4,000. He revealed that he is a successful real estate investor who had been blessed and wants to pay it forward.

"People complain that the price of real estate here is pretty high and I have benefited from that. I wanted to do something fun for the city of San Francisco, something that would get people excited. I'm giving right now about a thousand a day. For me, that's definitely manageable. I know that for most people it's more than they earn, but I'm in the top 1 percent. I can keep doing this."

@HiddenCash hopes that many people will join his finders keepers kind of game and will eventually engage to random act of kindness themselves.

"One example is you go to the toll booth and pay for the five cars behind you. Well, let's say the person behind you has more money and makes more money than you. You're still doing a good thing because maybe they're having a bad day or a bad week and you've lifted their spirits and brought a smile to their face. People that don't need money, per se, can still benefit."

Local news portal KTVU was also able to receive a call from the mystery millionaire.

"The last real estate deal I did I made about half a million dollars. I can afford to give a lot," @HiddenCash said.

He shared the same message through his interview with KTVU - for the people to pay it forward in the future.

"If people need the money for themselves, that's fine. But if they can share it that with others, that would be great. I've heard some heart-warming stories from people donating to charity and sharing it with other people who are less fortunate."

He shared further that he intends to bring his "game" globally in the future.

The Lucky Treasure Hunters

Both ABC News and KTVU were able to interview those who are lucky to get @HiddenCash's hidden treasures.

Richard Rodriguez and his partner raced to a street in San Francisco's Mission district Sunday after they read a clue that an envelope is hidden on a parking metre.

"It's about 10 blocks from us, so we did a power walk down there. When we got to the parking meter it wasn't there and we thought, 'Wow, how could anyone have gotten here so fast? Then a guy was driving by and threw an envelope out the window. I guess he didn't even have a chance to drop it off!" Rodriguez told ABC News.

"The money was great but it was also so much fun doing something like this. It was a scavenger hunt.

It's not a lot of money. It's not going to change your life. But the camaraderie it brings out in people is a lot of fun," Rodriguez said.

"People like to be right, to find clues and follow something to the end. Find something that nobody else has found yet," Matt Burkurt of San Francisco shared with KTVU.

Burkurt found his treasure tucked into a bulldozer parked on Lincoln and Great Highway near Ocean Beach on Sunday evening.

"On the front it says, with love, from Hiddencash," Burkurt described the envelope.

"Stand on top of the Caterpillar that's close to the water," was Bukurt's clue to where the envelope was hidden.

Bukurt said that he will use the money to threat his office for lunch.

"I didn't budget for an extra hundred dollars, so might as well give it to somebody else, right?"

"I don't think it's going to change the world, but for someone who found the money, especially if they were someone in need. I think it's a cool thing," Amoeba Music Manager Tony Green said.

One anonymous hunter found $100 in the sleeve of a We Are The World Record being sold at Amoeba Music.

"To me, it's that person's money. They can do whatever they want with it," hunter Sergio Loza of San Francisco said. He used his money to buy a gift for his niece's birthday.

"Thanks, it's a cool thing you're doing. A lot of people can use it nowadays. It's a good thing, keep it going," Loza said when asked for a message to @HiddenCash.