Boost MobilePromotion: $50 account credit when you buy a phone online and port your number from a non-Sprint network operator.
Status: Was due to end 1/3/16 but has been extended until 1/25/16.
Promotion: Free LTE phone at Boost Mobile Stores when you port a number from a non-Sprint network operator.
Status: Was due to end 1/3/16 but has been extended until 1/25/16
Promotion: Up to $100 off Boost phones at RadioShack when you port a number from a non-Sprint network operator.
Status: Due to end 1/9/16. I have no idea whether it will be extended.
Cricket WirelessPromotion: $100 bill credit when you port a number to Cricket.
Status: Due to end 1/7/16. Cricket has consistently been the most aggressive promoter so I think there's a good chance this promo will be extended. In addition, rumor has it that Cricket will bring back its old $60/month 20 GB plan tomorrow.
Update 1/8/16: Cricket has replaced the $100 port in bill credit with a rather lackluster discounted phones for port-ins offer: Motorola Moto E $9.99, HTC Desire 520 $19.99, ZTE Overture 2 $29.99, Microsoft Nokia 640 $59.99 when you port your number to Cricket. AT&T customers excluded. Ends 1/21/16.
MetroPCSPromotion: Free LTE phone at MetroPCS Stores when you port a number to MetroPCS from a mon T-Mobile based operator.
Status: Was due to end 1/4/16. However, the offer is still listed on the MetroPCS site under Current Promotions however fine print on the prono page still says the offer ends 1/4/16. I can't tell whether this promotion has been extended or not, but I suspect it hasn't and MetroPCS will announce something new in the next few days.