The owner of a large buy-and-sell coin operation based in the state capital wants to set the gold standard of professionalism with his new store in Minden.Allen Rowe, the 42-year-old owner of Northern Nevada Coin, said he's been collecting coins since he was a kid. "In college, I couldn't afford collecting anymore, so I started selling," he said. "Before I knew it, I was buying and selling my way through college."What began as a passion turned into a career. In April, Rowe opened his newest store inside the Boule Building next to Saletti's."The main reason to come down here was …