Some say it's less than living wage, but that's probably an exaggeration.

Confusingly, "living wage" in US parlance doesn't mean "the minimum you can live on", but rather the minimum needed to meet some set of quality-of-life criteria for the region after factoring in dependents. Exact definitions differ, but it usually hashes out to quite a bit higher than subsistence wages: when California was debating one a while back, I believe the number being tossed around was $13/hour in late-1990s dollars.

I don't know exactly what Walmart pays its employees but it probably doesn't qualify.