$90 is too much for that size!  I paid $400 out the door for a set of 31" hercules muds, same as the old cooper muds, a few years back.  They probably went up in price since they have a new tread pattern, but I see no reason why you should be paying $90 a tire for a lower brand.  See if america's tire co can get them, then find a super cheap price and they'll match it.