In Canada I use Rogers, which is pretty crap but it's the only GSM provider in my area.
They don't offer an unlimited data plan, and data costs 3¢ / kB. Which means every time I check my email it ends up costing me a couple dollars.
Compare that to Norway, where I use a pay-as-you-go card. Data costs ~0.3¢ / kB with a daily maximum of $1.50 (converted to USD).
As for the iPhone: $500 for a phone with no 3G, no GPS, no Bluetooth connectivity apart from the (mono) headset, can't download applications or games, a sub-par camera, no MMS, no video, and vendor lock-in...