I've sold a number of eBay lots outside the US, Rick. The US dollar is found everywhere. Your buyer can almost always come up with US currency to pay for your lot. I'm talking smaller amounts, of course... up to US$100 should present no problems to most bidders. Just state in your confirmation that you need payment in USA funds or currency.

As JimE mentioned, international money orders denominated in US$ are also available in most countries for a small sum and can be cashed or deposited in US banks for no fee.