Unfortunately the details of this dream are going to be limited. I had this dream a week ago, but wasn't able to post it right away like I wanted to.

The first thing I remember is being on another world. This world was characterized by the dullness of it. The sky was gray light like an illuminated night, but there were no stars or moon or even clouds to break up the monotony. The ground was smooth and dark gray with no grass or rocks or even the texture of concrete to break up the monotony. The buildings were dense, with great multitude, and, you guessed it, gray.
This world gave the impression of some form of Hell. I can't remember at what point it in the dream it was seen, but there was a letter. I also cannot remember the exact contents of the letter, but the gist of it stated that someone had transported all of the people of Earth to this world after the Earth had been killed and choked by smoke and pollution.
There was a person standing there with me from the beginning. He appeared to be some sort of guide here to give me an orientation. I think he was probably the one that showed me the letter I mentioned too. He told me about the unique economy of this place. Strangely, everything was sold in quantities of 6 for $125. It didn't matter what it was. He gave me a bunch of examples and showed me. Most of these items were ridiculous to charge that much for only six. I can't remember exactly what items he showed, but it should have been like 6 Q-tips or 6 eggs for $125. But then he showed me 6 new video games for $125.
At that moment, I realized that this weird rule could be abused to buy things that should be incredibly expensive at a massive discount. I also specifically thought that this place would be heaven for gamers, but hell for everyone else.*

That sleep was interrupted and I had a second dream that same day. The second dream was a pretty literal dream about the anxiety I have about a promotion I have coming up very soon. Since the dream was so literal, I'm not going to go into detail about it. But the one thing that did stand out was that I was seeing the number six again.*
After having the number six appear so strongly in these two dreams, it made me super aware of seeing six in my waking life too. Like that first sleep lasted six hours, then I checked my bank account and saw that I spent six hundred dollars in one weekend, then at work I kept seeing six again. I'm sure this is nothing more than confirmation bias. I'm just mentioning it because of how strongly the number six impacted me in the dream, but I have no idea what it could mean.