With plated custom coins, looks may be deceiving, but could help increase the perceived value.
Often when coins or medallions are made, the customer will have them minted in solid silver or gold. This certainly conveys high value, and makes the piece memorable for the recipient, but at times the costs of such a design can be prohibitive.
One way to help mitigate this is to have the custom coin or medallion made or minted in solid copper and then the plating can be done in silver, gold, or even nickel. Dual plating is still an option with this and in fact it allows the customer to get a bit more creative with what is added to the design of the coin due to the money saved on not having it made in solid gold or silver.