I would go for "price"price
or "cost"cost
if what you mean is "how many units of some currency can I exchange for a good or service""how many units of some currency can I exchange for a good or service". In scientific terms, "price" isthat would be a function of currency, as long you don't care which currency your sum is in and an. That is, any amount of some currency has a perfectly same value as a certain amount of any other currency and vice versa. For instance, an item priced at 100USD would be priced 86EUR or 74GBP or 11182JPY in some hypothetical world where taxes, exchange interests, inflation and that sort of things don't exist.