1 month before the release of BC, I bought every Assassin's Blade that I could - that'd be 10 of them at an average price of 100g. I enchanted every one of them with +15 Agility and threw them on the AH for 1000g each and spammed the trade channel letting people know they were out there and that after BC - high level enchants would no longer be allowed on items lower than 35. Since your average player didn't know what this meant, 8 of them sold in less then 2 weeks. Two were sold for 750g, but the rest went for 1000g. I kept the last two and put them on my rogue - b/c at the time 2 of them worked quite well (I also had a Shadowfang on him).
So my answer is 10 Assassin's Blades for the ballpark of 1000g (100g each).
Other items of note:
Petrospil Leggings - 20g
Bow of Searing Arrows 5g (right after BC came out and everyone was considering low level items to be worthless)
Gloves of Holy Might 10g
Staff of Jordan - 25g
Icemail Jerkin - 12g