Walmart is very aggressively anti-union. Yet there are places where it's one of the few firms offering any employment.

We are not talking here about Walmart's famous "greeters" ,but about people at the cashier level and above.   Starting salary for Walmart cashiers in its Las Vegas supercenter in 2004 was $7.65 per hour. It would be interesting to know what starting salaries were in Oklahoma, Texas etc---possibly even lower. At any rate Costco pays starting employees at least $10 per hour.   $7.65 is below poverty level. $10 is not.