The rate I paid was an introductory rate of 15 bucks for 2 hours--very reasonable in my opinion (in fact, I could easily see him justifiably charging more for it, but I guess he has a varied audience he has to price for). We met up on iCCup and used vent to communicate.
The basic structure was that we played games [in our case we played on Fighting Spirit since I didn't have a map preference] and then watched the replays and he discussed my play and how to improve (this was the default style--if I wanted to do something like ask about something or play a specific map or strategy, then I could do so, but since I didn't have any particular things I just went with the default).
Overall we played 5 games and looked at the replays in the 2 hours. I felt that he had a lot of suggestions to help me improve my Z (and also to an extent PvZ / TvZ by looking at what he was doing and from what he said). He provided very in-detail explanation of why he did what he did and the best courses of action.
One thing I particularly liked about it was that he acknowledged and accepted that neither of us are progaming monsters. We don't have flawless mechanics and reactions, nor will we. His advice allowed me to account for that and improve my play to a higher level without simply telling me to go practice hundreds of games to grind my macro/micro to be better.
Overall I'd solidly recommend him to anyone looking to improve their Zerg play. Yes, there are better foreigners out there, but his attention to detail and patience with the fact that I suck was very nice I'd say!