Gold Bar

Gold Bars are first seen in Luigi's Mansion. They account for 100,000G each and are often found in treasure chests.

Bars also are used for storing money in Paper Mario: The Thousand-Year Door and Super Paper Mario. Mario cannot use them in combat in any way, and he can only sell them for coins. If Mario buys a 100 items at a store, he'll get a Gold Bar for free. If he buys 300 items, he'll get a Gold Bar x3. In The Thousand-Year Door, the Underground Shop sells Gold Bars. Single Gold Bars go for 100 coins each, whereas a Gold Bar x3 costs 300 coins. Gold Bars initially appear to have no effect but, in a way, they allow Mario to carry more Coins. Gold Bars can be sold back to any shop for 90 coins, and Gold Bars x3 can be sold back for 250 coins. This ensures Mario a supply of Coins if and when he should need it.

Oddly enough, in Super Paper Mario, Mario can give a Golden Leaf to Saffron to turn it into a Gold Bar, and a Gold Bar into a Golden Meal, a worthless item worth 65 coins (as opposed to the Gold Bar, which is worth up to 110 coins). Doing the former of the two can be a very good way to get some quick coins because you can find Golden Leaves free, so then you can cook them and make a nice profit.