Comment by coldtea
ECC RAMs utility is overblown. Major companies often use off-the-shelves non enterprise parts for huge server installations, including regular RAM. The rare bit flipping is hardly a major concern at their scale, and for their specific purposes.
Most server CPUs require RDIMMs, and while non-ECC RDIMMs exist, they are not a high-volume product and are intended for workstations rather than servers. The used parts market would look very different if there were lots of large-scale server deployments using non-ECC memory modules.