my daughter works for River Island, she gets 1 full outfit every 6 weeks from the shop for free, and gets a 40% discount on all other things.
when she started she got 2 full outfits to start, she has a contract with set hours, and a good management in place, allowing her holidays within reason etc.
If I was your wife, I would use my retail experience to get a job within the sector that gives at least all of the above, Lidl pay the living wage in London at over £9/hour, there are good and bad employers out there, the secret is to settle in the good ones.