The 23-year-old midfielder, who was allowed to leave United for just £800,000 in 2012, is expected to arrive in Manchester on a private jet from Nice this morning to complete his return to Old Trafford from Juventus for a reported fee of around 110million euros (£93.2million) on Tuesday after the clubs revealed an agreement had been reached.
And Mourinho, who did not confirm the fee, believes prices may rise further.
“Football is crazy and the market has become crazy,” said the Portuguese, speaking after his side’s 2-1 victory over Leicester at Wembley in the Community Shield.
“What you think this season is crazy, you realise three years later it’s not crazy any more.
“There are players who cost £10million who are super expensive because they’re players (who are worth) £500,000 or £1million. What is expensive and not expensive in football I don’t know any more. I just know he is a big player.”
He added: “I don’t think Real were upset when they broke the record with Gareth Bale or Cristiano (Ronaldo). I don’t think it’s a reason to be sad – it’s a reason to be proud.”
Mourinho reckons United can help Pogba become one of the world’s best players because he will not have to compete with Lionel Messi or Cristiano Ronaldo.
“United is the perfect club to bring him to the level he wants to be,” he said. “The Premier League is the perfect habitat for that. If you want to be the best player in the world, if you go to Barcelona or Real Madrid you are in trouble because I don’t think the other two big guys will let you.
“Here he is in the most seen, worldwide, championship which is absolutely incredible, with a team which wants to bring Manchester United to the top again. We have everything to give him and we know the reasons why he wants to come to us.
“Money he would get at any big club. He comes because he knows the club, knows the city, many of the players and wants to be an important part of the project. Hopefully everything goes well.”
Pogba is set to become the final piece in Mourinho’s jigsaw follow the summer signings of Eric Bailly, Zlatan Ibrahimovic and Henrikh Mkhitaryan, and the former Chelsea boss acknowledges it has been a good transfer window for his new club as they aim to regain the Premier League title they last won in 2013.
He said: “It’s a good market for us. Bailly, Pogba, Mkhitaryan, Ibra. One defender, one midfielder, one creative, one striker. The squad is good. We need to work a lot, we need more work. I am happy for the next few weeks we have just the match on the weekend.”
Goals from Jesse Lingard and Ibrahimovic earned Mourinho his first silverware as United boss on Sunday, leading him to joke Pogba will have a tough challenge to force his way into his line-up.
He told BT Sport: “It’s amazing that such a good player is with us and finally we have him and he comes to a winning side, a side that won the last two matches, the FA Cup final and the Community Shield, so he has to work hard to come to the team.”