512 GB for $158 is not "cheap"
Case in point:
SAMSUNG 850 EVO 500GB - 125€
SanDisk SDSSDA 480GB - 114€
Crucial MX300 525GB - 123€
Well, yeah it's m.2 but even then, if you're on a budget you probably don't care what kind of SSD you buy, as long as it's an "SSD"