At auctions, you can bid with other managers to get players. Each bet will increase the price by 1 coin and some funds. As long as there is a new bid submitted in the last 10 seconds, the countdown will be reset to 10 seconds again.

The coins you bid will be frozen (not deducted) if you were the highest bidder. You can check your available coins in every trading procedure. Coins will be unfrozen if your offer is exceeded.

Also there's no perfect time for bidding. You have to be consistent in the search of good offers and eventually you'll get one.