I have no idea what options there are for a non-iOS user, but ...

There's an excellent iOS app called TurboScan. It's fantastic. Take a picture of your receipts and it'll convert the image to low file size, but high-quality, PDFs. You can then send those PDFs to your Evernote email and have them stored neatly in a notebook.

It's a fantastic solution for portable document scanning. And with the iPhone 4s camera being so improved over its predecessors, it makes great PDFs of receipts.