When buying on eBay (and elsewhere, presumably), PayPal likes to charge you a small fee to convert between two kinds of currencies. While this convenience rarely comes free, it may be cheaper through your bank. As redditor ilki points out, you can just route the conversion through your bank instead and likely save some cash in the process.
By default, PayPal handles the conversion for you. By switching to the second option presented to ilki during the transaction that allowed him to be billed in the seller’s local currency (“Bill me in the currency listed on the seller’s invoice”), then paid as normal. The bank needed to handle the conversion of the funds, but it came at a much lower rate than PayPal.