Mass bidding is all about bidding on as many players as possible and thus bidding on many of these players. This method is particularly efficient when bidding on players at the repulsion price (350 for non-rare gold cards and 650 for rare gold cards), as there is virtually no risk involved.
These players can then be offered every hour with a certain extra charge (depending on the value according to FUTBin). So you can make a profit without risking coins right from the beginning of FIFA.
Players should be chosen who have a popular league, a popular nation or both. This increases the chance that these players will be bought.