In every Passage just before the Boss Room, there is a Mini-Game Room which has 3 games where you can earn From-Medals to use in the Item Shop. Below is the list of games. When you went through a level, you collected gems which gave you a score. That score is the currency you use in the Mini-Game Shop. Each game costs 5000 except for the first time you go in the Entry Passage. Then it is only 2000 gems. The games are as follows:
This mini-game is considered the best one to get a lot of Frog-Coins from, although you might not get them quickly. All you have to do is hit the baseball the pitcher throws to you head on, and you'll hit a home run. If you hit it from the sides, you'll get a foul, and if you miss it, you'll get a strike. If you get 3 strikes, you lose. One helpful thing is that every time you get a home run, you won't have any strikes. After a while though, the pitcher starts throwing curves, fastballs, or even makes the ball turn invisible for half a second! Once you hit 3 home runs, you get a Frog-Medal.
This mini-game is the quickest way to earn Frog-Medals, but you don't get a lot at a time. All you have to do is make Wario jump over obstacles in his path while he runs on a tire. The beginning is simple, but once it starts speeding up, it starts to get difficult.
This mini-game is the hardest and the slowest way to earn Frog-Medals. What you have to do is create a face for a person. The concept is simple, but the task is hard!