Best mid- price Fisheye for iPhone 4?

On the net they go from 2 quid to 70…
My daughter wants a new gadget and as the iPhone camera is pretty good I'd best not buy the cheapest out there… Even if she's only gonna use it twice!
Thansk

On something like an iPhone there won''t be a lot of difference in image quality between the cheapest and the most expensive add-on fisheye lenses. Both will tend to give an acceptable image quality at the centre of the image and progressively less sharp towards the edges, and both will tend to cause colour shadows along contrasting edges particularly at the edges.

The fact is that fisheye lenses are a short term novelty and even the dedicated fisheye lenses used on interchangeable lens cameras like dSLRs they need to be really expensive before the image quality is uniformly sharp.

In short, spending more just buys you more expensive Christmas-cracker toy image quality. Buy the cheapest or something close to the minimum.