LONDON - Cristiano Ronaldo will finish his career at Real Madrid , the Portuguese superstar’s agent said Tuesday as he put a £300 million price-tag on the world footballer of the year. “He is the best player ever in the world. You can’t compare him with anybody else,” agent Jorge Mendes said of Ronaldo in an interview with the BBC. “If for any reason the club decide to sell him tomorrow for £300 million, someone will pay,” Mendes added. But the agent said there was no danger of his 29-year-old compatriot, voted the world’s best player for a third time last month — beating Barcelona’s Lionel Messi to the award — leaving Real’s Bernabeu Stadium. “Cristano Ronaldo? One billion. His buyout clause one billion, so it is one billion. It is impossible to find someone like him.”