When I inquired about installation costs at a boat show, the salesman wasn't sure but thought it would be around $500 to $800 for 1 pole, and a little less per pole for 2. If I did get power poles I would install them myself, but my boat seems to have easier access than most.
What Chobeemauga heard about needing 2 poles makes sense.
I really don't need power poles because I don't sit in one spot for a while, then move to another spot very often. Certainly not enough to justify the cost. My Minn Kota with spot-lock does just fine. If the wind is moving me around too much I just throw out an anchor. If I was fishing for money I might think different. But for me, power poles are just something else for me to break, have to work on, get my line tangled up with, etc.