I have almost the same truck, 07 2500 ccsb CTD, my tires were plus sized by the previous owner to 285-75-17, it had the Nitto terra grappler on it when I bought it and replaced them with the same. Very happy with the Nitto, also have them on my wife's LR3 for the winter and do well.
I have access to tire equipment so I do my own installation but u want to say it was still a bit over 800 for just the tires through a tire distributor.
Discounttiredirect.com is also a decent source, especially if you can get a sale.