Moot point. The USD price does not include sales tax, which is added on after the $50 price. I assume the €50 Euro price already includes VAT.
Sales tax in the US can range from 0% - 9.5%, depending on your location with a rough average of 7.5%. For those not familiar with sales tax, sales tax is a tax based on the final sale price and is paid by the consumer at the time of purchase, not the intermediary companies/distributors.