Tuesdays/Wednseday are best times to buy and sometimes fridays. Auctioning ends exactly 3 days from the time you put them on transfer list, therefore you want to think of when the margin is greatest for times that people are online in the current timing to the number of people online 3 days later. I think some people realize it so I seen on occasions where tue/wed alot of people come to try and bid for players because they know its the best time so its sometimes not as good. But on many occasions I noticed in the late evening times lie 9PM - 1AM Eastern time on weekdays you can find great value for players so I'd look around then as well