"Smartphone" these days really means any phone that does more than make phone calls. (If you can get on the web with it, definitely a smartphone.)
So Blackberry and iPhones are both smartphones.
Many places give away the device with the service contracts, don't let that part alone sway you too much. The service contracts are the thing. (If it's $100/ month for three years for example, that'd dwarf the price of a device pretty quickly!)
$50/ month seems to be pretty good. I have an insanely good deal on the Blackberry, unlimited data for $30/ month. That's highly unusual though (and only available to deaf people -- Blackberries were developed for us and they've kept some special pricing. Yay RIM.) (When I started with the earliest RIM text pager product, called a Wyndtell, back in 1999 or so, service fees started at $5/ month!)