Hey guys, this is my first contribution to mmowned, I have taken alot from these forums and I think it is time I give something back.
This is not an exploit as such, but it is a neat little trick to help towards the Epic achievement, which can potentially go a long way.
After my Naxx 25 run today, I realised i have enough Emblems of Valour to purchase the ilvl213 boots from the vendor. Because I have only just recently leveled 80, I was still fairly undergeared, and groups that asked me to link my Epic achievement realised I wasnt so epic
But then I realised with the new re-selling system put in place in 3.1, you can buy the boots, equip them (and get the credit for the Epic achievement), resell them to the vendor, and buy a cloak, rings, librams, idols etc, equip them, and resell back to the vendor, vastly helping towards the achievement, and allowing you to purchase the item you want and keep it eventually.
Anyway heres a screenshot, in my case i bought a libram with an ilvl of 213, then decided I wanted the ring so I vendored the libram back, and helped the achievement.
Well there you have it, I hope this helps people