The simple formula is Icy Cloak -> disenchant to Large Glowing Shard.

Icy Cloak http://www.thottbot.com/?i=5035

The recipe for this is sold by the trade goods merchant in Southshore for the alliance, I do not know for the horde.

My costs were simple.

Frost Oil - 1 per 1gp - 1.3gp
Mageweave - 20 stack for 80 - 90sp
Thick Spider Silk - 2 for 80 sp
Thread - 4.25sp each

So, approximate costs were 1.3 + .70 + .8 + .085 = 2.9gp rounded up on the high end, 1 + .6 + .8 + .085 = 2.5gp on the low end.

Stranglekelp sells on the AH at 4 to 4.5 g for a stack of 20, and it sells FAST! The reason for this is that it's used in a ton of potions that people use to level their alchemy skills. For some reason, there is a perception that it is difficult to find and collect, but I've been collecting it on a daily basis in huge quanitites with relative ease.

All you need to do is go to Zoram Strand in Ashenvale (west side of Ashenvale) and swim out into the ocean a little. Start from Zoram Strand in the south and swim north, collecting Stranglekelp as you swim. See the map below: