How much should it cost to replace a head?

Tryed replying earlier, not sure if it went through. To answer your question no I wasn't trying to replace the spark plugs, I was actually driving when the combustion blew the spark plug out and broke the ignition coil when it blew out. I took it to an Acura dealership and they told me I would have to rebuild the entire motor ($14,250)<---not going to happen. So I asked them to just replace the plug that shot out and the ignition coil, which they did. Within 5 min of my trip home the seal on the new ignition coil broke and allowed air to escape which made it run rough. I got it home and haven't drove it since. I'm not a mechanic what so ever but it seems like there is a problem with the threads on the head not being able to seal around the plug.

ok,i understand,the plug got loose and blew out of the head,took the threads with it.like i said they do make a special tool for repairing this,and you need more tools to do this repair,and be quite handy with taps,sockets,ext.,torque wrenches and so on.that price sounds very high to me.i know for a fact that they can remove the head and either repair it or put a new head on it for way less than $14000.00.at the acura dealer or honda dealer.that is a honda motor in your car.i did a google search of yor problem a few minutes ago and watched a video and detailed instructions on how this repair is done,very detailed info.i do not see why they told you that they need to rebuild entire engine.if i were you i would check around at some different places and get prices from all.it is hard to find people to do work on your vehicle without them sticking it to you.you cant trust any of them unless you know the very well.i wish i could help you,but i am lost for words on this.ask your friends if they have anyone that does that kind of work.ask everyone.research your problem and yo will find something somewhere.you need someone who works on and knows honda,acura engines.these are unique little powerful engines.sorry i cant help.....................steve...Gastonia,NC.....................

Thank you for the advice Steve.