Actually, I would disagree with nearly everyone here. 30,000 a year is roughly $15 an hour, and that is a reasonable rate for a somewhat experienced designer if you're hiring them full time. It would be a bit more in an expensive major city such as San Francisco bay area, but before we were offshoring most of our design, we were regularly getting excellent freelance us-based designers for $20-25 an hour, and two of them said they'd work for $15-18 on a full time basis.

Now... if you're going with high-end design studios or designers with a well established reputation, $35 to $75/hour is not at all uncommon, though every designer I've talked to is finding it harder and harder to command those rates, particularly in adult.

As for the amount of work... my experience is you have to watch them fairly carefully because, as Lloyd said, without supervision, they'll be on Manhunt or Myspace or somewhere. A TGP gallery should take an experienced designer no more than 1-2 hours (and often less) unless it's really fancy, a tour page with a lot of custom work on the images and such might take between 6 and 15 hours, again depending on the complexity. A designer who is fresh out of school will probably take longer, but one who has worked in any sort of production shop should be able to turn out stuff fairly quickly.