[aynyc]

Just to be sure, you mean 10x between subsea cable and regular armored fiber cable, not cat6 I can get from best buy.

[iptrans]

Yes, not that there's a large difference. Best Buy has pretty large markups, especially on short CAT6 cables.

You can buy subsea cable for $10-$20 per meter.

EDIT: the cost depends on how many layers of armoring you require. Deep sea cable requires less, shallow sea cable more.