Usually less that 48 hours. To turn off go to My Sales and then the Discounts tab.
There was an email sent out last month saying that they "automatically" entered everyone into a discount program. You were supposed to reply to them sending them an email saying that you wanted to opt out. However, many, many artists who opted out, were automatically opted in by a "glitch" in the system, and CGTrader has apologized for that. Some artists never got the email.
