(NewsNation) — March Madness surpasses even the Super Bowl when it comes to the amount of money wagered, especially this year with legalized sports betting becoming a much bigger proposition.

For the tournament overall, an estimated 45 million Americans were expected to bet a whopping $3.1 billion on the games this year. As teams have been knocked out of the bracket, some of those bettors have gone by the wayside, but very few can resist the allure of the Final Four, especially with a historic Duke/UNC game in the first round.

And when it comes to that game, while Duke is only a 4-point favorite on the line, the Blue Devils are a 2-1 favorite with the bettors, many of whom are likely counting on the emotional boost of playing in legendary coach Mike Krzyzewski’s final tournament to carry the team to victory. In North Carolina, Duke and UNC flags seem to be sprouting from every car, with some cars carrying one of each to signify a house divided.

Duke is also favored to win the entire tournament, no matter if the opponent is Kansas or Villanova in the final game Monday night. UNC is the longshot to take the title, at nearly 5-1 odds.

As far as prop bets go, those “fun” bets that have naught to do with who wins or loses, you can place a $100 bet on whether either of the weekend’s games will go into overtime to win $950. There have already been seven overtime games in the tournament, so who knows?