CurrencyGuy Alexa Skill
Currency Guy can get you the exchange rate between two specified currencies based on today's date. By saying" What is the rate of US Dollar to Chinese Yuan", there would be a voice response returned with something like "Based on 4/1/2016, 1 USD = 6.45 CNY" and meanwhile a card would be generated in Alexa app in case you want to see the returned result visually.
PS: Currently not all currencies are listed, more work to be done in the future, hope you like it!!!