Walmart offers the Apple iPhone 6s 32GB Prepaid Smartphone for Straight Talk, Net10, Total Wireless, or Walmart Family Mobile in Space Gray or Rose Gold for $149.99 with free shipping. (Straight Talk charges the same.) That's $25 under our November mention of this prepaid phone with another carrier and also the lowest price we could find for a prepaid version today by $25. (Most sellers charge around $200 for this prepaid phone.)
With these companies, it might be easier than you think to negotiate your monthly bill down.