Originally Posted by rogue_librarian
It's 4GB alright. Straight from the horse's mouth
Speicher: 4GB; bis zu fünf vorgerenderte Bücher
Memory: 4 GB; up to five pre-rendered books
Site does suggest you are right as do all the others i've found today but I have read something else that explains the pricing a bit more, apparently it's a subsidized price by carriers probably only when you buy a phone and contract along with it.
Also read the IOS/Android App has to do all the book rendering and it can only hold 5 books at a time despite the 4gb which doesn't make a lot of sense.