you got a $50 click? that may be for an ad not related to iphone because sometimes google displays ads about keywords which you had been searching before they came to your site(may be finance/health related)
Always health/finance related keywords are not high paying, it does happen that other niche are also quite good if you really try them out!
When I did a search in google adwords site of things for "apple mac" the highest bid was around $6 I then just did a basic search for "apple" and the highest was around $11. You must therefore be having direct advertisers on your website? Not people just bidding in the open content network...
I have a site with this and other similar longtail keywords, although the average is $1-$1.50 I'd say $50 is an exageration.
whta he means is that the keyword : Apple or Apple Mac will pay maybe 1 to 15 dollar a click when you are lucky. But maybe they right line of words like : Eat a Hot Apple Mac Can be wuth 1000 dollar a click ... who knows
Well, I am very new to adsense. I wonder how did you get $50 per click when I get $0.01. Do you have any suggestion?