Dozens of customers have bought his T-shirts, which are made to look just like the one he wears, emblazoned with “staff” on the front. Caine had his shirt made last summer, when his family was on vacation in Palm Springs. At a souvenir stand, he asked the attendant to write “Caine’s Arcade” on the back and then spelled out what he wanted on the front: “S-T-A-F-F.” He did not know exactly what the word meant, but he had seen it on workers at the mall.

“I knew it made them important,” he said.

Now he charges $15 for a copy of the shirt. When one customer handed him a $20 bill on Tuesday afternoon, he pulled out a wad of bills only after asking, without a hint of sarcasm, “Do you need any change?”

While money from the Web site goes into his college fund, he is able to pocket most of the proceeds from the arcade and its merchandise.

“He’s always been trying to figure out ways to make money,” his father, George Monroy, said, standing in the shop his own father opened in 1955. Before creating the arcade, Caine tried his luck at selling yard signs supporting sports teams from the front of the store. His only customer was his father’s secretary, and she bought only one after Mr. Monroy had handed her $5 with instructions to pretend that she really wanted one. Caine later attached a skateboard to a box filled with sodas and chips bought from a vending machine and traveled up and down the block hawking them.

Mr. Monroy does most of his business online these days, so there were few walk-ins. But Nirvan Mullick, the filmmaker who made Caine famous and flush, had simply wandered into the store, where he saw the boy’s creation and became his first customer. “As soon as I saw him, I was immediately sucked back into my childhood,” Mr. Mullick said. “He had such focus, took it so seriously and just believed in what he had.”