Buying/selling sub-section

I was thinking that adding a buy/sell section would help people out, like the Item Exchange section, it has both a buy and sell.
I think that adding this to all of the other market sections would make threads more easier to read and would help a lot more people.

If this has been suggested already i'm sorry :S i couldn't find it anywhere, the one that's similar to mine would make the whole site too big.