One way to get more money is to make a new manager and pick a team you want. And then turn off your xbox an restart it with out saving. And then create up to 10 new players with their stats at the max and put them all on your selected team. Then start the new manager account and select the team and then sell the players to get new better players. You can put them on a team that you want to play for and then sell them. Caution this hint has a 50/50 chance of not working.

If it says you need a minimum number of 18 players that means you cant sell one of your players until you buy one.

If you try to buy a player and it says a minimum of 18 players that mean you can't buy a player from that team because they only have 18 players.