You get a WORSE deal on contract, but it is slightly more convenient, and in the past the only way to use iphone (inertia at work).
Case A
Subsidized iphone 5s costs $200. The cheapest contract plan on Verizon is $80. ATT is $70, but that includes only 300MB data. PLUS MONTHLY TAXES which I don't have the info on, but EASILY $10 more a month, probably twice that. So lets say MINIMUM $80+10 * 24 + $200= $2,360 for a basic plan or $110+10 x 24 +$200 = $3,080 for 4GB of data (high usage).
Case B
Purchase iphone for 650. Monthly plans as low as $39 (Ultramobile) $45 (GoSmart) and $40 (Spotmobile). $40 + 24 + 650 = $1,610
So we have $1,610 vs $2,360 or a minimum difference of $750. Enough to buy a 32GB cellular ipad and get 200MB of free data from t mobile.
There may be reasons for buying an iphone under contract for some people. But price is NOT one of them.
That's a totally unfair comparison. Ultramobile, GoSmart, or Spotmobile ≠ AT&T, Verizon, T-Mobile, or Sprint.
Actually, the cost benefit of no contract is that in California and some other U.S. states, you are taxed twice for part of the phone cost if you get it on a contract. That's like a $70 difference, but I think it ends up more than balancing out.