1) Lots of deals for new handsets from sources other than the carriers;

2) New to the USA market, lycamobile has interesting all you can eat paygo plans on the TMO 4g network. http://www.lycamobile.us/en/national-plans

3) I use TMO's daily prepaid rates. ($2-$3 per day all you can eat) since I only use the phone for 10 days per month. http://prepaid-phones.t-mobile.com/prepaid-plans
VOIP and SMS via Wifi fill the gaps for most of the month.