@amit It is weird how that often seems to work out. In many cases you have to use something only a very little bit for it to be more cost effective. I guess maybe companies prefer the simplicity and predictability of getting a known level of income from their customers so they want to encourage that with some slight discount?

However! That's not always the case. My phone plan, which is through Ting, is WAY cheaper than my old plan with AT&T, (and to a slightly lesser extent my wife old T-Mobile plan) and it's pay as you go. I have only adjusted my usage a very little bit since switching, and even if I hadn't I would still be saving money. I used to pay around $86/month for a grandfathered in unlimited iPhone data plan with AT&T, and my wife used to pay just over $50/month for her plan with 1gig of data (I think?). So we were paying about $136 per month all told. We switched over to Ting and now our combined bill is between $50 and $60 most months, sometimes as low as around $40 (and on rare occasions a little higher. The highest bill we have ever had was $87, and I think there were some trips and time away from any kind of reliable wifi involved then).

If I used my phone very differently it might not be cheaper (I have a friend who basically does most of his work on his phone and used their payment calculator to find that he was better off staying with his current traditional pre-paid plan), but I would have to use my phone in a radically different way for that to be the case for me.