Here are some 235R15 truck tires.
http://www.tirerack.com/tires/TireSe...er=15&x=56&y=5
I don't think I'd buy any used ones in that size, or at least be careful when they were made. They truly haven't put that size on trucks in well over a decade, maybe closer to 15 years. And dry rot on tires is worse than low tread.