Hi!
Please always specify your ticket ID or your account email. It will help to identify you and provide better help. Fortunately, I found your previous ticket ID and checked your transactions.
Your Paypal transaction was in GIP currency that caused double conversations USD->GIP->USD.
Please note that Paypal doesn't know the currency of your card and set it in their own way. In your case, they thought your card in GIP currency as the card issuing bank situated in Gibraltar. To avoid double conversations in the future and pay in USD for USD purchases you need to contact Paypal support and ask them to change the basic currency of your card to USD. Usually, they do it very fast.
Earlier it was possible to set the currency of your card in Paypal manually without contacting the support, but as I know, for now, they disabled this useful feature and you have to do it only by sending the message to support.
Please let us know if you have any additional questions.