You can buy phones without signing up with a mobile provider. If you want to buy the phone from the provider, they'll usually offer you the subsidies. The big providers don't make it very open that you can actually get a plan without buying hardware.
If people want to go the subsidization route, whatever (I personally happen to think that if you can't afford 500$, maybe you shouldn't buy the hardware - get a 50$ feature phone instead). It just irks me if people think they are getting something for free. I hear "phone x costs 0€ at provider x" all the time, so people definitely don't understand this.
My personal take is to avoid the maze of operator prizing completely (50 free minutes between 9am and 11am, but double prize on weekends, except for SMS which are free on a full moon), so I only sign up for plans that I can quit at any time, and with the lowest recurring fee possible.