This is from the Wal-Mart website:
New T-Mobile Monthly4G $30 Unlimited Web & Text with 100 min of talk •Fund your Monthly4G or Pay As You Go plans
•Exclusively at Walmart
•No Annual Contract, 30-day Monthly4G plan
•Great for Facebook, texting, games, and streaming music/video
•Nationwide 4G Network
•No Annual Contract
•The $30 Unlimited Web & Text with 100 min talk plan works only with T-Mobile Phones purchased from a Walmart store or from Walmart.com.