Robinhood stock grew a lot and got expensive in 2025. It will only be worth its current price if the business' growth continues.For years, Robinhood Markets (HOOD +7.32%) stock looked kind of hopeless.Shares of the online brokerage -- the first company to "gamify" stock investing and hook a new generation on investing during the pandemic's lockdown era -- surged in the days following its July 2021 IPO. But it took mere months for Robinhood to give back all its gains and then some. By the time 2022 rolled ar ...