There are people out there who know they're supposed to have a case, but don't want to spend a lot of money on it. They assume it's going to break or get scratched up anyway, and don't really care what it looks like. For those people, there's AmazonBasics.
Amazon doesn't offer a lot of options for its phone cases — for the iPhone X, there appear to be only three styles and a handful of colors right now — but you can't beat the price and convenience. When it wears out, you can order another one with a few clicks and get it in two days.
Amazon's textured iPhone X case comes in blue, grey, and black and costs $11.99 on Amazon's website (it's available for Prime, too).