Do you want bolt on or weld on?
For weld on you're looking at between $230-$550 shipped
For bolton it's around $400-1000 shipped
I personally just got some Stubbs HD-SKO sliders from
Richard Stubbs welded on they ran ~$360 shipped. It seemed like the best value to me as he has an excellent reputation, was great to deal with, and seemed to be the best find (looks, durability, & cost) for me after looking for almost a year.
Here is a thread with pictures of mine.
Other weld-ons include
Trail Gear &
4xInnovations. Neither of these companies list 4th gens on their site but I have emailed both and they both say they'll make them for ~$30 more than the 3rd gen ones.
The cheapest bolt on sliders I've seen
Rocky Road Super Sliders which (IIRC) are about $409 + shipping but a lot of people don't trust the way they attach to the frame AND body. They also don't stick out very far from the body and aren't a good recommendation if you plan to use the sliders as steps.
Other bolt-ons are from
Demello,
Shrockworks,
White Knuckle Offroad, and a few more but run $475+ before shipping.
Hanna Quality has also made sliders but I couldn't find very much info about them other than the people who buy them like them.