If anyone still wants to a scanner that's portable, I can recommend the Cannon LiDE 30.
I picked one up on sale many years back as part of a shop so my end cost was something like $14 for it. I love it because it's the same profile as my MacBook and will fit side by side in the case with it (I have a 17" screen, so you will be bummed out if you try to pair this with a small laptop).
I like that it works in the background and powers off the USB bus. I don't have to fiddle with camera settings of flattening receipts, so I can scan receipts in the car and they magically appear in the right folder.