Well, our rock shopping adventure has come to an end. I think we are getting about 2 tons of a thin flagstone and a ton of some other crap to build the wall. And a ton of sand. About 1900 bucks delivered. I'll post some pictures once it shows up.
I also priced, but wasn't smart enough to document, some bigger rocks, which I think were about the size of let's say half a loveseat with the back chopped off, for around a 100 bucks. I didn't buy any but I may head back down to the store and get a couple. They are bigger than what I typically find around here and not that expensive, and if I can add more to the delivery of the other junk it helps.
As I think about my pond project, which is the real root of all this nonsense, I'm likely to spend a real sh1tload on rocks. They had some nice looking stuff, like the below, for 230 a ton, with some negotiating (likely to mean 10-15% less) but I could use this entire corral full a couple times over. Then also need some pea gravel to fill in empty spaces.
I've come to the conclusion that diesel is significantly less expensive than rocks. I need to find the thread posts with the rock screening jigs so I can copy the style and start digging holes out back. I think, with screening, I can find a lot of usable rock for, basically, free, and I'll stumble upon some good, bigger, rocks in there too. There's nothing really stopping me from digging 2 acres of 15 foot deep holes to explore.