Cricket Wireless is now offering the Microsoft Lumia 640 for $29.99 with a new activation. That number changes to a nominal $9.99 if you bring your number from another carrier.
If you go for the more recent Lumia 650, you'll need to pay $119.99 and there's no number transfer benefits.Microsoft Lumia 640
The offer is valid with any of the carrier's available plans, except the basic Talk and Text plan. The plans range from $40 to $70 a month with $5 off of that each month if you enable the Auto Pay option.