question

In most cases when you use receipt validation, you'll be sending the currency code and price paid as part of the call. In any case where a price is not passed in, we use the price specified in the catalog (RM for the USD price - so 99 RM is $0.99 USD).

But yes, each price in the catalog or store definition is distinct. So an item set up with two different prices - one in VC and one in RM, could be purchased with either.

However, please note that setting a price in a catalog or store makes that price available for purchase of the item by any player, if the correct call is made (and, of course, the player either is actually paying the money in question, whether real or virtual currency). So your best practice here would be to not give the non-full account players any way to get the virtual currency in question. If you want to give the player VC that they can see but not use, as an incentive to get them to upgrade, use a separate virtual currency for the VC purchase prices of the items, and when the player upgrades, use a Cloud Script to transfer that balance over to the VC used to define the purchase prices.