Price cuts, of course, are a way of life, and no one should be surprised that competition drives down prices. In my view, most of the iPhone GPS navigators are priced too high. I think somewhere between $35 and $50 is about right considering that you are providing all the hardware. Hardware solutions have really plummeted in price, with many selling for close to $100.00. The advantage of the iPhone solution is there is only one device to carry, but navigation stops when a call comes in.
I'll have a roundup of my favorite GPS apps in a couple of days, but if you are ready to go a 30% discount on the TomTom is a pretty good deal, especially if you need to navigate in both Canada and the U.S. The well regarded Navigon app [iTunes link] is selling for $89.99, but watch for sales on that product as well. I know a lot of people are holding out for the free Google Navigator for the iPhone, but there is no guarantee that it will ever hit the App Store.
Thanks to Steve for the tip!