I just tried adding adding iphone as a broad and exact match to one of my campaigns, and it wants a 15p (about 30c) minimum bid for both. My campaigns and my site have absolutely nothing to do with phones of any type, so I'm not sure what that tells you, but it's an answer.
ok the minimun could be 15p or c. this is because of the quality score. the problem is with 15p it wont be on the first page of results!