Best time to sell is when it's busy, right?
back when I still 'needed' inf I'd stockpile all my 'good' drops in the base and then list them on the weekend. The feeding frenzy is as reliable as it is insatiable.
The Nethergoat Archive: all my memories, all my characters, all my thoughts on CoH...eventually.
My City Was Gone
The weekend always provided for me on my lazy marketeering escapades. I'm really lazy. I basically buy 5 of a single IO, craft them, sell them for a profit, and repeat. I only work a -single- item at 5 or 10 at a time and I've gotten so much money from doing it when the weekend rolls around 
Made 300mil while outside playing with my kids.
I love weekends!
...that is all!