To make any edit to your Marketplace Thread, you need to send $30 per thread to Make sure you put your userid and thread link in the PayPal comments. You then need to PM one of the marketplace mods with the thread link, transaction ID and the email address you used to pay with. 

Once we've verified the payment (which can sometimes take up to 48 hours), we will make the changes and you'll be notified immediately.

Find out more information on editing your threads.