Cell phone plans are the most annoying one for this; I remember at one point the advertised price for the plan I was on was $118 ($99 per line, plus $19 per additional line, I had 2 lines). The amount I actually payed was a bit over $165. The big 3 providers had different amounts of tacked-on fees and at one point I called up one of them to ask what my actual bill on a particular plan would be 3 times and got 3 different answers. This made it essentially impossible to price compare plans.