There's a wide range of what is considered 'BB'.. Some of these prices have to be Indonesian which is a shop grade with numerous voids. Top tier and actual BB in my area...and I get contractor pricing... is @$130 for a 3/4" x 4x8 sheet (before the pandemic I paid about $85). Look at the stamp on the side of the sheet which can help determine it's origin....or ask the lumber supplier.

Rich...I may have to ship a unit from GA if that is actual BB!