Is it unhealthy to drink pig’s blood? Like out of a glass? 
Not that I want to…
How much does it cost from the butcher?
I would think so. Blood and meat should be cooked to kill the little bugs. Particularly pork and chicken should never be rare. Ewwww!!!
Planning a prom prank ala Carrie?
well i dont know about drinking it fresh, but well, Filipinos make a very good dish called Dinuguan out of it (trust me, we trick the uninitiated by calling it “chocolate meat” and then telling them after what it is :))
Recipe: http://www.tribungpinoy.simplenet.com/recipes/dinuguan.html
There was an article in a magazine like Outdoors by Tim Cahill, and he described a trip to somewhere in SE Asia. He had dinner with a local, and the meal was fresh snake. It is a tradition to drink the snake blood before the meal is served. I guess that Tim was only able to keep it down for about 5 minutes. At least he drank it, the trooper.
I worked in a pig slaughtering factory for 1.5 years. In the “kill” department I’d say about 70% of all people had blood all over themselves by the end of the shift. Naturally some of this would get inside a persons mouth. Not to mention the weirdos that would actually eat little chunks of meat(obviously bloody).
I vote for not harmful.
If you get Certified Pork Blood, you should be able to drink it raw, if that is your intention. Certified Pork Blood will be available through a large meat supplier or slaughterhouse, though, you may be able to special order it from a butcher. Wouldn’t have a clue to the cost, though.
Just recently made Blood Sausage last week in culinary school, and it is a mixture of pork blood, bread crumbs, cream, and a mixture of onions and spices. Tastes sort of livery, to try to describe it.