In Dragon Quest IX for the DS, there are special items called mini medals that you can use to purchase some regular, and rare items.
In Dourbridge, visit the pirate king Cap’n Max Meddlin and you can give him the mini medals for a reward. It’s cumulative, so keep giving him the medals you find.
4 Mini Medals – Thief’s Key
8 Mini Medals – Mercury Bandanna
13 Mini Medals – Bunny Suit
18 Mini Medals – Jolly Roger Jumper
25 Mini Medals – Transparent Tights
32 Mini Medals – Miracle Sword
40 Mini Medals – Sacred Armor
50 Mini Medals – Meteorite Bracer
62 Mini Medals – Rusty Helmet
80 Mini Medals – Dragon Robe
Once you give him 80 medals, he’ll sell you rare items using mini medals as currency instead of gold.
Prayer Ring – Purchase With 3 Mini Medals
Elfin Exixir – Purchase With 5 Mini Medals
Saints Ashes – Purchase With 8 Mini Medals
Reset Stone – Purchase With 10 Mini Medals
Orihalcum – Purchase With 15 Mini Medals
Pixie Boots – Purchase With 20 Mini Medals