Jim's "Equipment" suggestion after you login to My Account is the best bet since existing customers may not all see the same offers/prices. When I do so online, I don't see the "fine print" that you will agree to. If you want that much detail, you can read
http://www.dbstalk.com/attachment.php?attachmentid=5521&d=1143587313 but that version is at least a year old and has probably been updated.
The only significant thing to remember about DIU is that any receiver you get under the program comes with a $6/month ViP lease fee. If you "upgrade" and end up with just that receiver on the account, you still pay the $6. If the receiver didn't come from a DIU agreement, only the 2nd, 3rd, ... receivers on the account have the lease fee. Other than that special case, it is pretty much the same price and 18 month commit you would encounter as a new subscriber. The Special case does make it the same price to keep one previous receiver and add a ViP as it is to replace that previous receiver and have only the ViP.