I found one on the Market Board on Ridill for my Relic quest for a measly 4k. I'm not sure how the prices would be on your server or if I was just lucky, but I don't see why there would be such a wild discrepancy on Odin.

Failing that, just buy the sword sans materia and materia separately from the MB, and then put your 'request materia meld' flag up (shouting for someone to help meld the items for you is also an alternative).