The lottery is a optional little side game found in Dragon Warrior II. You will need a lottery ticket, which can be received most easily from merchants. If you buy more than one thing, they more often than not, will give you a ticket.
Some monsters will randomly drop tickets as well for you to get. Also there are tickets found in treasure chests at Charlock Castle, as well as Cave to Ronne.
Below is the list of towns you can play the lottery in:

Beran
Hamlin
Leftwynne
Lianport
Wellgarth

The Prizes you can win are:

1st Prize: 3 Sun Symbols = Golden Card
2nd Prize: 3 Star Symbols = Wizard's Ring
3rd Prize: 3 Moon Symbols = Wizard's Wand
4th Prize: 3 Water Symbols = Dragon's Bane
5th Prize: 3 Heart Symbols = Medical Herb

Dragon Warrior Casino. Please play responsibly LOL.