I'd happily pay $2.99 (or $4.99 or maybe even more) for a great Android Instapaper app over using "save pages for viewing later offline". The reason being that Instapaper deals with multi-device sync properly for me. For me, the real "magic" of Instapaper is being able to bookmark interesting looking articles on my laptop before I leave home in the morning, read some of them on the iPad at a cafe on the way to work, read/bookmark some more in gaps at work on my work machine, and skim through articles on my phone while in the queue at the bank or post office... As a mobile developer, I alternate between a few phones, and I really miss the Instapaper iPhone client when I'm carrying an Android device...