I use Pocketbook IQ, which is a 7" Android tablet. It is not state-of-the-art, and it runs an older version of Android, but with a dedicated app I can read comics comfortably in landscape mode set to width, and I only scroll once up to see the lower part of the page. I find it works well enough, and it has the advantage of color. It has 1GB of internal memory, a cable to connect it directly to PC, and an SD card slot (I think it can take up to 4GB cards).

If she mostly reads B&W comics, maybe getting one of the larger e-readers? I'm not in the market for one, so I'm not familiar with the prices, unfortunately. The IQ model sells for $180 on their web page: http://www.pocketbook-int.com/us/products/pocketbook-iq

They have several world wide resellers so you can go to their international page ad choose a location that suits you: http://www.pocketbook-int.com/welcome-pocketbook

I hope that's been helpful!