If you are on a major carrier in the US and have an unlocked phone with a post paid account you can switch to Sprint for a free year of service until 6/30. Just enter your MEID and current phone number to test if you qualify. I am not getting it to work with a FreedomPoP Sprint SIM or a T-Mobile phone so you may have to switch to Verizon first. If you don't have a phone Virgin Mobile is offering a $1 if you buy one, also unlimited*
*Offer ends 7/31/17. Excludes taxes. Regular rate of $50/month applies after promotional service period. Only with AutoPay.