We Need More Writers!
As many of you already know, a huge content update is coming September 9th, 2014. We've hinted at things to buy in the past, but now we finally have some more concrete ideas on what's changing (particularly with regards to crafting).
It's time to start purchasing crafting mats. ALL OF THEM. You should especially be purchasing leather, which has the greatest room for growth amongst the crafting disciplines.
Each crafting discipline will have the ability to create a back piece that can then be upgraded while leveling the discipline.
While I'm hoping that leather will be a primary component for every back piece (that would greatly help the wounded market of flipping leather), that is not a gaurantee.
The other thing you should be buying across the board are cheap fine quality items for the purpose of salvaging them once prices on materials go up. Think of it as an alternative method for stockpiling.
Your last real chance to stockpile will probably be this weekend, so get on it!
Lastly, sell off or salvage any crafted weapons/armor you have lower than level 80. New items coming with the patch will likely ruin your sales.