A High School Student Building Integrated Circuits
I have really wanted to do this myself.  Buy some older fab equipment, and produce NAND chips.  Start selling 4TB SSDs for $100 or so.  It's ridiculous how long the price-fixing in the SSD industry has been permitted to persist, and someone needs to take them out.  We don't need even 10nm production for SSDs or anything.  Go ahead and fill a standard 3.5" drive cage with the device.  Since the chips function mostly in-parallel, you get speed increases just from concurrent use.  And I'd imagine you might find a subversive company willing to sell you controller logic on the cheap.  Just so absurd that such a basic part as NAND chips can even get treated like a premium item despite being in basically every product of any kind created in the past 10 years.  Any other component like that is commoditized and dirt cheap, especially when they contain no rare materials.