My long time best friend likes to buy things cheap from chinese vendors all the time, most are replicas. I like to support local economy but everytime I buy a computer component it's made in China, Taiwan, Indonesia, etc. So either way I'm supporting their economy and then we buy all that stuff overpriced.
That case looks pretty good, but I really doubt what it comes with. I think it comes with one front intake fan, but it might come with none for the price. Looks nice for $5 but you'll never know unless you own one.
My best friend has bought some things for that site. They take more time than usual to arrive but they do arrive.
It seems like a hit or miss on that site. You are not actually buying items from aliexpress, you are buying from 3rd party merchants. It's kind of like ebay. Im sure many of the merchants on the site are honest , but a lot of them seem to be scammers as well. A $5 case just looks sketchy. The metal used to make the case would cost that much. When you factor in the factory, the labor, and the shipping, the cost would far exceed $5. If you do take a chance and buy the case anyways, use a prepaid debit card or a virtual credit card so they can't steal more than just $5 from you.