As of know, the system only have buy/sell player. In the actual, there is a system that called "Loan" player.
With this type, we can starting bid with 1Gold and also have an option to permanent or not based on the description loan.

In the future, the player need to sign a contract, based on their happiness,, they can stay or go from the club and another player can propose to buy them.
But its depends on the team, so not just buy a player with the higher rating, but you also required to maintain the happiness each player.

Having fun!

Maybe the time of the loan only 24 hours, so it will different with buying a player..

so, not just build your team,, but maintain your team

GOod