From what I remember, she's in the 'poor' side of the Walton family. Her uncle and his kids are the mega rich ones.
Edit:
Ann's Cousins:
Christy Walton and family US$28.2 billion[2]
Jim Walton US$26.7 billion[2]
Alice Walton US$26.3 billion[2]
S. Robson Walton US$26.1 billion[2]
Ann and her sister:
Ann Walton Kroenke US$4.5 billion[2]
Nancy Walton Laurie US$3.9 billion[2]
