Take Amazon payments, for example:
"Q: What countries and currencies are supported by Amazon FPS? Amazon FPS allows U.S. as well as international customers to use major credit cards to make payments on Amazon FPS-powered websites. ... All transactions are in U.S. dollars."
Emphasis mine, because that little aside renders Amazon worthless to me.
Source: http://aws.amazon.com/fps/faqs/
* Have a phone with a UK-based billing address available for our registration service to contact you. * Have a credit card (issued by a UK-based bank) * Have a current account with a UK-based bank. (Optional; you can set this up after registration)
http://www.amazon.co.uk/gp/gateway-eu
So unless in you're in one of the few countries supported by Amazon Payments, you're out of luck (as far us Amazon Payments is concerned).
I know people in India who order books from Amazon US and pay in USD using their India-issued credit card.
I think it's just a matter of UX to show the price in USD to a foreign audience.
There are risk implications from having to predict currency movements. Or I could take futures contracts, which is difficult and in itself a warning flag to banks if I have low income. There may also be complicating tax implications from trying conduct all my business in USD and then converting the profits.
It would be easier for me, by far, to conduct my business in my local currency. This is not an unreasonable constraint.
Off the top of my head, https://payments.amazon.com/ is a great alternative. Not sure how the rates stack up, but I definitely trust Amazon more than I trust PayPal. I'm sure there are more alternatives available, I don't know why so many people insist on using PayPal. I think Amazon allows donations cause kickstarter.com uses it, and you don't necessarily get anything if you fund a project. I'm guessing the tricky part here is the "donations", but PayPal certainly has a poor customer satisfaction record.