Try doing this in order to get three free cards and 10,000 DP. Keep in mind that this can only be done once per save file.
Step 1 - Connect your PSP to the USB port on your PS2.
Step 2 - Insert Yu-Gi-Oh! GX Tag Force 2 into your PSP, load the game, select "Database" and then "USB Connect".
Step 3 - Insert Yu-Gi-Oh! The Beginning of Destiny into your PS2, load the game, select "Database" and then "USB Connect".
If done properly, your prizes should be won thereafter.