Yes, apparently it because of NAND shortages. 

any reason why there's a shortage? I don't exactly know how the supply chain works. 

Huge demand apparently. I heard other stuff but I'm not sure how legit that is 

Yeah it doesn't look like its getting better, and prices are up 20-30$ or more for some 

last year there was a rumor from a crappy site you most probably know of, i read that  prices of ssd & mem cards & anything flash storage related price would be increased incrementally throughout this year to the end of the year nearly 40-60% by the end of this year , guess they were right , & if they're right , this is just the beginning sadly

shit then I should grab a new ssd sooner than later. Some time ago I bought 2 adata 480 GB ssds for 109 each (separately, months apart). Friend JUST bought one for 119, and now it's 137