Worked at a Wal-Mart for about eight to nine months. I worked the evening shift, that is, from 2 PM to 11 PM, with an hour lunch break in between. Most of the time I was in the back storage room, unloading the big semi trailers that came in daily, sorting the products, and putting them onto palettes to get pushed out to the sales floor.
I was getting paid minimum wage ($7.25 an hour in Texas, or just shy of $60 per 8-hour day), and worked 5 to 6 days a week with randomized days off. Paychecks came in every other Friday, each check was about $630 before it got to me, and about $400 when it did. Thankfully I was still living at my parents' place, I don't know how I'd survive if I had to pay rent.
The working conditions weren't terrible as most people assume, I worked in the back storage lot a bunch as basically a product-mover. That is, myself and a team of people would unload the big semi trailers that came in daily, we'd sort the product onto palettes and we'd push them out to the sales floor. Then if we had extra time in the day, we'd unpack the palettes and put the product on the shelves until the night shift came on. You got a 15-minute break for every 4 hours of work, so effectively two in the day, and you could add them onto your lunch for a really long lunch break if you wanted.
Also I've seen a lotta people here comment that the store greeters have a horrible job, and let me tell you that they absolutely don't. I had to cover for a greeter once, and let me tell you, I wish I had their job. All you do is stand at the entrance to the store, say hi to people, ask if they need help (and direct them to the customer service desk if they do), and give stickers to children. And you make like $11.50 an hour. Mint.
What made working there so horrible were the people. Management didn't give a crap about most of the workers, and despite our team constantly being understaffed (we were supposed to have 11 people to unload a truck... we had 5) we still had to meet the incredibly sharp time schedule. It didn't help that about half of the workers were assholes anyway, and the constantly changing schedule and consistently horrible pay was enough to force me out.
I don't hate Wal-Mart as a franchise though. I appreciate not having to go store-to-store to find my stuff, and because I've worked there before, I can usually find stuff pretty quickly without asking for help (which for an introvert like me is always a plus). I just don't want to work at one, ever.