As high as them trucks are now, that price is in the average ballpark, but I just couldn't give $9k for a truck with 230k miles on it. I gave $12k for mine with 110k miles on it last year, 2005 model. But it's ext cab, not crew. That one Chad had just like you posted a pic of there had 150k-ish, crew cab, clean as **** with brand new BFG KO2 tires and it was priced at $12,500.
Me personally, I'd take my time and try to find one with 150k or less in the $10k range. They are out there, every now and then, even the older body 2002ish models will pop up. Just seen one not too long ago a buddy was selling, like 140k miles, 2002 stepside ext cab for something like $9500.
Friend of mine just got a deal on a crew cab just like you posted with around 150k miles for $6500, super clean truck, but one of his wife's relatives hooked him up on it, was a trade in at a Chevy dealer.
They are out there, just takes time to find the right one and you gotta jump when you find one. When mine was sitting outside at the body shop my dad works at in between them pulling it in and working on it, they had 2 people stop in trying to buy it. Those trucks hold their value good, probably as good as or better than a Tacoma these days. Do a KBB value on mine and it will tell you it ain't worth but $9-10k, yet every one on Craigslist, most with a lot more miles than mine, are listed for $12-13k. The market is crazy on these trucks.
Another point for the mileage argument though is this. People seem to not think twice about buying a Duramax, 7.3L, or Cummins truck with over 200k miles, and pay good money for one too. I'm sure the same gamble could be taken on a half ton gasser and probably be no better or worse off. People say diesels last forever, but how much do they spend maintaining the engines? I see all sorts of diesel failure threads/posts all the time, rarely see gasser failures. For what one spends maintaining a high mileage diesel over the course of ownership, could easily equate to buying a 100k mile junkyard LS to replace the current one in that truck if it did decide to **** the bed beyond repair one day.
Also, are you only looking at half tons and are you only considering crew cab vs. ext cab?