Huh?
4x 30€ is not 150€ on my calculator (DDR4 RAM I bought for my Intel NUC which I use as my server)
Now if we talk about DDR5, 2x 16GB, ECC and registered Kits...That might fit.
The kit I bought was 148€ in April 2023. Even now it's 125€.
And it's not really an isolated case of cheap ram...