If you just created a Google Payments account to make your first purchase or added a new payment method to your account, you may see a $1 charge.
This is a temporary authorization fee in place to make sure your card is active and online purchases are available.
The charge will remain on your card for a short time showing a "hold" or "pending" status.
Apple may also charge or reserve a small amount solely for the purpose of verifying your account, but it will be removed after your payment method has been verified.