The 25-year-old, who cost $29 million in 2015, has scored five Premier League goals this season and supplied three assists to help Liverpool climb to third in the table.
Klopp, the former Borussia Dortmund coach who took the Liverpool job a few months after Firmino arrived at Anfield, said he felt at the time it was a great deal for the English side.
“I thought, immediately, 'What a good transfer for them'. When I heard about it I thought, they had made a good signing, because I felt pretty sure clubs would have paid a lot more for him,” he told reporters on Thursday.
“In Germany, some people don't know where it (Hoffenheim) is but, if you play your football there, then you feel it is a tough place. So, you know what a decent job the scout did, whoever brought him in for that price.”
Klopp, who has brought players such as defender Joel Matip (Schalke) and goalkeeper Loris Karius (Mainz) from the Bundesliga to Liverpool, denied having spoken to anyone about Firmino before his move to England.
“The first thing I did when I left Dortmund, I took my phone and deleted all the numbers so I was not reachable. So, I didn't speak to anyone to offer advice about Firmino... but he was... one of the best in the Bundesliga,” the 49-year-old said.
Liverpool host 17th-placed West Ham United on Sunday.
Original source: Firmino was a bargain buy, says Klopp