After you run a scan, go check your snatch list for good deals. You can either buy from that window or press the buy all button at the bottom. I think you have to press ctrl + shift + alt then click it. It will place a bid or buy out every item in that list for you.
I have added one time things to the list to buy lots of a item at a set price. Like when someone puts up a ton of infinite dust as singles at a low price. Add the item to the snatch list and let it do the work of buying all of those.
Netherweave cloth is something that I have in my snatch list. I can convert it to bags and it sells very quickly. If I am getting too much of it, I lower the price I will pay just a little bit. If I don't get enough, I bump it up or I just manualy check on that item.
My snatch list is my "buy it all" list nomatter how much there is at that price. If I have that too close to market price, I could easily buy more of something then I can sell.