Currently Virgin Mobile is offering Unlimited Talk/Text/Data $1/month for 6 months.
In addition, they are offering previous iPhones pretty heavily discounted. After 6 months, the price goes up to $50/month. Still reasonable. You can cancel any time. This is prepaid so no taxes or other fees.
iPhone 6 starting at $199
iPhone SE starting at $159
iPhone 6s starting at $349
iPhone 7 starting at $449
iPhone 7 Plus starting $569
iPhone 8 starting $699
iPhone 8 Plus starting $799
if you have an iPhone 6 or better (SE is better), then you can switch over for just $1 per month. Unlimited Talk Text and Data.
What else? You become part of the Inner Circle. This probably doesn’t appeal to many, but it does have some perks if you travel. Also, you get a free companion flight.
Not as good as their previous $1/year promotion, but still pretty good and it seems that deal is over now.