The top rated players are usually very expensive in FIFA Ultimate Team. In FIFA 18, Cristiano Ronaldo is the highest rated player, starting at 94 overall. His amazing in-game stats mean that he will be extremely sought after in Ultimate Team squads, but not many will be able to afford him.
Playing matches and winning tournaments is the main way most people earn FIFA Coins, while others purchase FIFA Points to buy packs on the market. This allows you to sell packed players for coins and then save up to buy players for your Ultimate Team.
Another way to make coins is to use the Transfer Market for trading, buying and selling players for profit with the intention of purely using them for making money rather than ever using them in a match. Trading in FIFA 18 may seem daunting at first, but follow these tips and tricks to help you turn a profit!
Source : http://www.goal.com/en-us/news/how-to-trade-in-fifa-18-ultimate-team-and-top-coin-making/1coyd0lcnrteu1ifuqtto3pygb