A Fantasy Football league contest in which prizes are guaranteed before the competition actually begins, not taking into account how many people actually participate in the contest. Guaranteed prize pools can be very attractive to potential participants, since they have a clear idea of how much money they could possibly win.
League hosting websites know that Fantasy Football drives in the most money of any sport fantasy league, so they take advantage of it by opening hundreds of contests for thousands of people. Websites will open contests for a limited number of people, charge an entry fee, and use that fee to pay back the top performers in the contest. They decide on the guaranteed prize by multiplying the cost of entry fee by the maximum number of contestants allowed, subtracting the money they are going to take for running the league. If the maximum number of participants is not met, overlay occurs and the site must pay the remaining entry fees!
First, make sure to choose the tournament you enter wisely. Different types of tournaments have different benefits than others and can help you win money much more easily. If the main reason you are playing is to win money, look for a tournament where there is a good chance of overlay, or where you can have multiple lineups entered at once. These types of tournaments increase your chances of winning!
Second, make sure you are choosing your players with the tournament in mind. Knowing that the wide receivers on your team will bring in the most points each week will help you make smarter drafting and salary decisions. Do not go into the tournament blindly, you won't do as well as other teams!
Lastly, recognize how many other players you will be competing against. Tournaments with several hundreds of players will be harder to win than one with 50 players. If you're just starting out, try to start smaller and work your way up to bigger and more difficult tournaments!