Costa trialled unsuccessfully at his hometown team Atlético Clube Lagartense. At age 15, he left Sergipe and moved to São Paulo, to work in the store of his uncle Jarminho. Although he was never a professional, Jarminho had connections in football and recommended his nephew to Barcelona Esportivo Capela, a team from Ibiúna in the south of the city set up as an alternative to drugs and gangs for youth of the favelas. Before joining this team, he had never been coached in football. He turned professional at the club, earning around £100 per month, and competed in the under-18 Taça de São Paulo despite a four-month ban for slapping an opponent and dissent towards the referee. Although he was sent off in the first game of the tournament, he attracted the attention of renowned Portuguese agent Jorge Mendes, who offered him a contract at Braga. Costa's father was apprehensive of sending his son to Europe, and suggested he instead sign for nearby Associação Desportiva São Caetano, but he was adamant that he would take the opportunity.