TheUltimateDoomer666

I found a thread from a few years ago on some site where someone said the original big box releases of DOOM (including the US floppy disk mail-order release) are "next to worthless" and that they "wouldn't pay $5 each for them."  So uh, why are the two mail-order releases on eBay more than AU $800 each?  Did their value increase by $800 in like 4 years?  Are they overpriced?