Kuszczak signed for Brighton this summer after spending six years on the sidelines at United.
The Polish keeper claims that Fergsuon stopped him joining a string of clubs across Europe over the last 12 months with unrealistic transfer demands.
He told The Mirror: "For the last year, I had the chance to move to many good teams.
"I always said that I want to play, I asked for permission to leave. At United, they said they would let me go. But for £5 million.
"Shay Given had three years on his deal at City and was sold to Villa for £2m. I had one more year at Old Trafford and they wanted £5m. This sum of money was unacceptable."
The 30-year-old's performances for Brighton have earned him a recall to the Poland squad for Tuesday's World Cup qualifier against England in the absence of Arsenal duo Wojciech Szczesny and Lukasz Fabianski.