Yes. From 2008-2013, there has been nearly a 20% decrease in the average monthly mobile wireless price, mostly due to decreased prices in mid and high volume plans, and new market entrants.
This statistic is supported by Industry Canada (Backgrounder—Facts About Competition: More Choice, Lower Prices):
[T]he average price of wireless services has decreased by nearly 20 percent...
The Canadian Radio-television and Telecommunications Commission (CRTC) says something a bit different (CRTC issues annual report on the state of the Canadian communication system):
In 2012, [...] Canadian families spent an average of $67 per month on wireless services, up from $61 the previous year.
That CRTC statistic is about monthly spending per family, rather than the average price of wireless services.
The CRTC also distributes a report prepared for them by Wall Communications Inc. titled Price Comparisons of Wireline, Wireless and Internet Services in Canada and with Foreign Jurisdictions. At section 4.2, they review the price of wireless service in three different service level baskets over the past four years.
Here is the data in table form going back to 2008:
(CAGR = Compounded Annual Growth Rate. Note that some generally minor changes in methodology apply year-to-year. Averages calculated on a market share and population weighted basis.)
From 2008-2013, basket 1 has a 6% decrease, basket 2 has a 26% decrease, and basket 3 has a 17% decrease.
These averages may be lower because of cheaper, new entrants to the market, rather than incumbents. This would explain you and your friends not noticing lower prices if you haven't sought out plans from new market entrants.