spark plugs on 2006 Ford E-350

I want to know roughly what it will cost to replace the plugs. I read thy are a pain to change and break off alot. I have 94000 on truck.

2 answers
If there are no complications the labor time to replace the plugs is 3.5 hours according to one labor guide I look at.
just to add to Pat. it 3.5 but seems 5 or better if it has rear heat or any other accessories.

Roy