Some years ago, it was easy to find ECC modules with a so small price difference.

From that time, I have a few old computers with 64 GB or 128 GB of DDR4 ECC memory.

Unfortunately, after the passage to DDR5, DDR5 ECC UDIMMs have become hard to find, and even when you could find them, the price difference could be as high as 30% to 50%.