Lottery Pick

An optional bonus item in Paper Mario: The Thousand Year Door. For 10 coins, on the west side, you can buy a lottery ticket, a 4-digit number. Everyday, a new winning number is posted. You can change your number for another 100 coins.

Prizes
Prizes are when a number matches in its exact spot and are given by the brown Bom-omb after checking the winning number:

4 numbers - ? 3 numbers - ? 2 numbers - ? 1 number - Life Shroom 0 numbers - Mushroom

I have never 'cheated' (see below), but if just one number gives a Life Shroom, they should be very good prizes.

Gamecube Clock
The winning number is regenerated at midnight according to your Nintendo Gamecube Clock. Therefore, it is possible to cheat and try infinite times by resetting your gamecube clock.