-No matter what team you are in Manager mode, purchase the best free agents in the transfer market. Sell them during the same transfer market window so you do not have to pay the high salary. Since they are free to you, once you sell them you can get the added millions to your bank account.
-Make any players you do not want as young as you can. Make them a forward with a role of CF. Set all their attributes at 99 and sell them in Manager mode. They should be worth at least $70,000,000.