Probably the easiest way to make coins without really trying in FIFA. Every week there are SBCs and objectives set which rise the price of cards. Early on keep high rated players of common nations and leagues. Often you will need 83 and higher rated squads to complete SBCs. Save these early on and they could sell for maximum value for an SBC. Make sure sell them at the start of the SBC for maximum profit. Keep an eye on key times such as 3pm onwards during day times. EA usually make new ones live at 6pm.