You are probably on the new transfer market, which has limited players. These free players are free agents without a team. You dont have to pay any club so when you put a bid in you are only bidding what there salary is. So it is significantly less, and virtually free. When you are at lower levels these free agents are easy to buy. In higher levels it gets difficult but can still be beneficial to your team. The free agents will show up with a "(f)" next to there value on the transfer market. Hope i answered everything you were looking for