I believe the advertised wage for MF on the BA recruitment web site was £17000 - £20000 per annum. This included allowances and a productivity percentage. This equates to $27200 - $32000 per annum at $1.60 = £1.00.
This is considerably more than than the Wal-Mart wage you quote. Yes some of the allowances will be spent down route but what is the value of the other benefits relative to those offered by Wal-Mart i.e. staff travel.