Pontiac: ignition, pontiac grand prix, wd 40

Question
2000 pontiac grand prix se 6 cylinder.
When I try to turn the key off it won't turn completely off so that I can take the key out.  The engine is off but the key won't turn all the way.  Sometimes if I let it sit a while it will turn off or if I turn the wheel it will turn off.  It has been doing this for about a month and seems to be getting worse the last couple of days.  My husband put some WD-40 on it and it helped a little.  I was just wondering what you think might be wrong with it and how much it usually costs to fix that.  Thanks

Answer
You either need an ignition lock cylinder or the housing. It is a fairly common problem. You'll want to get it fixed as soon as possible because it will stop turning at all.
Not sure of the price. Most of the ones that I get are still under warranty.