Cost of the song i bought

So i recently bought a song in iTunes "Lost Stars" by Adam Levine which is the number 1 song right now in iTunes. It says there that

it cost 0.69 USD so i computed it using the live exchange rate USD to PHP which is about 30.36 PHP but when i checked my balance in my card the transaction costed 87 PHP which is 1.9 USD. why is that? Note: bought in the Philippines of course