Using Brickseek, I just picked up some for $7.00. One store didn’t seem to be In-stock [though Brickseek said in-stock], and another store did have stock for $15 as Brickseek said. The Walmart website does not show accurate inventory. The in-stock items were on the top shelves not price marked.
http://brickseek.com/walmart-inventory-checker/
UPC#: 778988592533
SKU: 130151748