The former England international sealed a one-year deal at Loftus Road yesterday after completing a medical.
There were reports that QPR's board members were reluctant to agree a move for Ferdinand due to his wage demands, but Redknapp has insisted that there were no issues regarding money.
"We'll only bring in players who want to come here," Redknapp said in a press conference. "Ferdinand's wage demands were low. He just wanted to come. It was easy."
United has joined QPR after leaving Manchester United at the end of last season following a 12-year spell at Old Trafford.