Beau Spencer Thompson AKA 1,000.000 Cubs (he will hit that goal on April 5th) left a good paying job and his day to day work is selling on EBay.
He does a daily podcast. (he's off for the next week while at Spring Training) and is happy to give advice on the process. And he sells mainly cheaper cards with a few expensive cards tossed in and almost never a graded card.
Also, he does very well promoting a monthly show in Madison Wisconsin which has approached 175 tables for a one-day show.
Here is a link to his podcast from Monday
https://www.youtube.com/watch?v=ipkEKLy0G3o
Regards
rich