Hang out in the "for sale" section for some used tires. My friends and I have all bought used tires and the only difference is the price, really. A couple years ago you could pick up a set of 33x12.50x15 BFG MTs for under $400 bucks (that has probably changed since then).
Check other forums including (omg hate this) jeep specific forum. There are always guys moving up from 31s -> 33s -> 35s. Their left overs are your gain.
And be flexible. I bought my TSLs with the "wrong" rims (incompatible lug pattern with my rig). However I dismounted them, sold them and bought the correct rims. When it was all said and done, I had a set of kickass off road tires for under $500. As mentioned earlier, I know a lot of people who have been able to get a good set of tires for this price.
If you drive a Jeep/Toyota, you are more likely to find a set already mounted on some basic steel wheels. This is even easier for you. Just get them balanced and put em' on.
If you must buy new, then look at Futura MTs at Pep Boys. They are the same as Cooper SSTs. Also check out Dunlop Mud Rovers. I've known a lot of people who run these with good success.