Starting April 23rd through April 26th, Sprint customers who port in their Wireless number to T-Mobile at a Costco/Wireless Advocates or Car Toys location may be eligible for a $35 bill credit. This port-in credit is in addition to the activation fee waiver Costco members receive as part of their membership benefit. This offer is available only to Sprint customers who port-in their numbers to T-Mobile. Remember, the offer is only valid in Wireless Advocates (Costco) and Car Toys locations. Additionally, a new 2-year service agreement is required. Bill credits will post within three bill cycles. This promotion is not available to Puerto Rican residents, FlexPay annual/monthly subscribers, employees, special dealers, accounts that have an Activation Fee waivers and upgrades.