-Play as Arsenal and purchase Robert Pires for £17.5M. After acquiring him, go to find player, type "Pires", and Robert Pires with a different club and only worth £75,000 will appear. Purchase him and Man Utd will place a bid for the more expensive Robert Pires at a price of £23M. Accept and Pires will go to Man Utd, but leave you with a profit and the other Pires.
-Have a rich club such as Manchester United or Barcelona, then purchase players from the club you want to make richer. e.g. St. Johnstone (Scotland) Gerry McMahon for 7.5m, Nathan Lowndes 6m etc.