Now a days you could use probably any carrier, all of them have come out with no contract. It ranges from 30 to 65 dollars per month for your usage depending on minutes and data.
for eg. T mobile gets you unlimited talk, text and data for 55 including taxes(approx) similar for verizon etc
If you need cheaper options go for Simple Mobile. There's lot of options available. Get any new phone or old unlocked phone you have and get connected.