I would imagine that a cheap android might be a bit of a gamble - some of them aren't great in terms of touch sensitivity - I didn't even know Paper 57 existed outside of the iPad.

Looking around at the stylus market ( for iPad anyway ) opinions seem all over the place. For the moment I've ordered a cheapo one TeckNet 2 in 1 Micro-Knit Fabric Tip Capacitive Touch Screen Stylus Pen and Fine Ball Pen

- excuse the copy and paste font - ( I have plenty of 'free' ones that are rubbish ) and some people seem to think that some models can make you end up scratching the screen if used without care.