I am in pursuit of Level 4 seller status on TCGplayer.com because at Level 4 you can list an unlimited number of cards and received the options to list with more shipping varieties and options.
In order to get to Level 5 I have to complete at least 51 sales, with at least 90% of those reaching their destinations in the required shipping amounts of time that TCGPlayer requires AND with a 100% feedback score.
So far I've reached Level 3 seller status which is having only completed at least 11 sales, I'm up to about 18 now, under the same strict selling requirements.
I've got some more work to do for even having reached Level 3 it still opens my account up to being able to list up to 50,000 cards which is a massive step up from the 100 and 200 maximums of Levels 1 and 2.