The time frame I'm usually on at is Monday - Wednesday 11am EST - 7pm EST, and Thursday - Friday 11am EST - 3pm EST.

Normally I check myself away in game and leave it running when i go away.

This is not a set in stone time frame but close enough. also if i won an item or if your bought an item from me, i normally add you to my friend's list till the trade is done so i can PM you as well when you come on to Guild Wars.