I doubt you will find a promo code for online.net, actually before a day or two they raised prices for their servers without any notification. BTW you will get much more resource with less price at hetzner.com.
@Dr. McKay If you just go to our main website, you will see that we are currently running a no setup fee sale on 9 of our dedicated root servers (unmanaged servers). You don't need any promo code to order these servers. In addition for any of our other servers without setup fees (auction serves, cloud servers, etc.), you do not need a promo code. --Katie, Marketing