Go Arsenal, buy Robert Pires for £17.5M. After getting him, go to find player, type "Pires", and Robert Pires with a different club and only worth £75,000 will appear. Buy 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.
Go a rich club such as Manchester United or Barcelona. Buy players from the club you want to make richer. e.g. St. Johnstone (Scotland) Gerry McMahon for 7.5m, Nathan Lowndes 6m etc.