Ask Mr. Smarty Plants

Pachira aquatica, also known as the Money plant, is a special kind of bonsai. It is a tropical wetland tree native to Central and South America, where it grows in swamps. The Lady Bird Johnson Wildflower Center is dedicated to the protection and propagation of plants native to North America. However, living in an apartment in New York, we can see it would hardly be possible for you to be growing a field of wildflowers. Most plants used for indoors decor are non-native tropicals and semi-tropicals because their environment can be altered to suit their needs indoors.

The Money tree is considered to be a harbinger of good luck but it doesn't actually sprout money. It has been especially associated with China and is often given out at Chinese New Year.

We were unable to find any research about the dangers of metal residue from a pot damaging the plant over time. We are more concerned with the possibility of poor drainage if the plant is placed directly into a non-porous container. Every plant, even one originating in a swamp, needs good drainage for its roots to survive. We are assuming you did not plan to drill drainage holes in your metal container. If you are worried about metal residues, you might consider lining the metal container with a heavy clear plastic. Now, to establish some drainage, first raise the "floor level" of the pot with some pebbles. Then, you can choose either to place the potting soil directly into the container, or to plant the tree in a porous pot, like terra cotta, or a plastic one, both with drainage holes and that will fit inside the metal decorative pot. You can add moss from a florist around the edges to conceal both the plastic liner and the interior pot. The link above will give you more information on the type of potting mix, size it may grow to, sun exposure, etc.