I just started a subscription with AngiesList. Supposedly, you can cancel prior to the end of a year and get your fee back -- I've had it less than a month, so don't know about that. I did like that promise, though, as one of the concerns I'd had with AngiesList would be if enough people were subscribed and contributing in the area you're interested in.
It seems to be a fairly nice system. Like Yelp or Google, it basically only lists those places that have reviews. There are a couple of things I am not impressed by -- they 'rank' reviews given by people who do not use the service of a company as less important than those who do use it. On the face of it, this makes sense, but if a company impresses me so badly up front that I walk out, it seems that information would be useful in a review. There's also no verification that I can see -- there's a place for a company to say, for example, "yes, I am licensed in the state of Iowa" but I don't see that AngiesList actually validates that to be a true statement.
I know I got some sort of discount which I'm not sure is still in existence. And I don't see any current 'invite a friend and you both get something' type deal going on now, or I'd send you that information.

There seems to be no easy way for me to find out current prices - I think 1 year for me was going to be about $15-$18. It certainly seemed reasonable and if your son is alone in another city it might be worth getting simply to get recommendations for health care, plumbing, and general maintenance in addition to mechanics if he's in an apartment instead of a dorm.