To buy any player for free, do the following. As an example, Rivaldo can be signed to Man Utd. As ManUtd, go to Rivaldo and put in a bid of £0, press "Offer", and then "Yes". With another team under your control, such as Liverpool, go to Rivaldo and put in a bid of how much the player is worth, press "Offer" and then "Yes". Still as Liverpool, click on the action button and select "Change Transfer Bid". Now click on the small triangle in the top left hand corner, then click on Man Utd (their name will appear once you have clicked on the triangle). You now have total control of the transfer bid. Just click "Accept" and your bid of £0 will be accepted. Withdraw Liverpool's bid for Rivaldo, and providing you can meet the player's wages, you will sign the player for free.
For example, if your team is Arsenal and you want Beckham, create another player and take control of the desired team (Manchester in this case). Once done, go to the player's profile (where it lists his attributes) and click on "Discipline Player". Make him hate you or release him. If not, you can change the transfer status. Now with Arsenal, offer Beckham £0 or £1 million. Eventually he will accept.
Go to the "Editor" file in the Championship Manager 3 installed files and click it. Click on "Championship Manager 3 Editor" to see a square box which should say index on it. Click on the little arrow at the top of the box. Then, click on "Data". Next, press "Open". The "Editor" should then open and say "Processing". Click on "Clubs", then go to the search menu. Click on "Find". Enter the team of your choice that you will use in the game. After that, click on the amount of cash available for the team. Change it to "14999999999M", then click on "Save". Exit the editor and load the game. Start a new game. This will not work if this is not done. Your team will have the maximum amount of money. Note: You can also change how much skill the players have in the editor, as well as your club's reputation and other attributes.
Sign these players as soon as possible as they will be one of your top signings:
Vance Warner David Woozley Dean Chandler Malcom Christie Carl Laurie Peter Prospar Jamie Shore Daniel Montenegro Martin Palermo Leyder Preciado Bosco Bizzarri Pablo Aimar Tonton Mokouko Sixto Peralta Silvestre