The Jaguars made their first big plunge into the free-agent market Friday by continuing their bargain-basement shopping philosophy and luring three players with opportunity rather than big money. After signing one unrestricted free agent, linebacker Geno Hayes, in the first three days of free agency, the Jaguars added three more — defensive tackle Roy Miller of Tampa Bay and running back Justin Forsett and cornerback Alan Ball of Houston. The Jaguars didn’t break the bank to get them signed. They got Hayes for two years at $1.950 million and added Forsett and Ball, who both made $700,000 last year, at two years in the $2 million range. Miller also got a two-year deal, but it was closer to the two-year , $4.5 million deal that defensive lineman Terrance Knighton got from Denver when he left the Jaguars.