For the most part, commerce had collapsed. No one traded with anyone they didn't know - no one had enough to risk it. In their little valley, one might trade a cow for a hog or two, but it was a balance of meat for meat, not money. The vast farmlands spoke of by the grandfathers no longer existed, though most everyone had a farm. Instead of fields of corn or wheat as far as the eye could see, now each farmer grew enough to feed his stock and his family, and to see him with another crop next year. If he grew enough to trade, he was either wealthy or foolish.
There were things to trade for besides food in their valley. There was the man who cut firewood and hauled it to town in his big wagon. There was the woman who turned their wool into fine material, both heavy for winter use and light for year-round use. She even made yarn for those who wanted to knit sweaters or crochet scarves. She was paralyzed from the waist down so her husband managed the dying vats, giving everyone as much color as there was to be had. One bolt of material could bring in a whole side of beef and a bushel basket of yarn might bring in a hind leg of hog.
The creek that ran through the middle of town kept the mill running during the summer months, and for every ten fifty-pound sacks of flour the mill turned out, the miller kept one, and if the customer didn't bring in that much, well he got a share of what was brought in.
There was also the man who kept their wagons repaired and their horses shod. His brother tanned hides and turned them into harnesses and parts thereof while their uncle, now too old to manage the heavy task of tanning, made shoes and boots to order.
And like in all gatherings of people, there was even the bar, and like in the rest of the small community, the bartender traded for his wares. He turned out an acceptable brew with corn and sugarcane, but he too needed to eat. A full wagonload of corn and cane could earn your name on an entire barrel of brew exclusively. Few people could part with that much for such a reason, so it wasn't uncommon for several people to share a barrel, and hash marks were used to keep track of the shares.
If a family didn't have enough meat or crops to trade, there was always labor. It was considered the height of bad manners to turn down someone offering help for fair pay.
There were those who traded long distance. Who knows where they came from or where they went, but there was a couple caravans that came through every year. Their arrival was cause for a celebration as they brought such things as salt and fine pottery and needles. There were other things too; they traded most anything for most anything. These traders were well known and had been making this journey for as long as most of them could remember.
The grandfathers of course remembered different days and different ways, but those were long gone. It was the occasional stranger that was watched closely. If he stayed around, he was generally required to show the color of his blood, one way or another. After all, he might be a mec scouting them out. Everyone knows that it was the mecs who destroyed everything. And those that remained were still trying.
The last president had thought it was the height of intelligence to make robots that could fight their wars for them. And when that seemed to work so well, they made some to be police. It was supposed to be so simple; the soldiers were programmed to fight a certain battle, and when it was over, they got new programming. Same with the police, only something went wrong. Pretty soon it was the mecs against the humans and they had been well built.
Those built for police work were the hardest to detect; they looked and acted very human. It was this that made them so dangerous. They couldn't, however, bleed.
Though it had been nearly fifty years since the last of the open battles were fought, the farmers guarded what they had furiously, and it wasn't uncommon for those gathered in town to approach a stranger and ask to see his blood. The traveler, if he was human, usually offered his hand to be sliced. A small cut across the palm was sufficient. Course if he needed his hands, a cut across the back of his arm worked too. If he resisted, his punishment was rather more severe, as he was fought to the ground and pummeled until blood showed from one or another of his wounds - fists didn't always draw blood soon.
One hot summer day, many of the farmers were lounging in front of the bar, when a solitary stranger rode in. His horse was well cared for, but dusty from the road, as was the stranger himself. He dismounted and tied his horse next to the others at the rail. "I'm looking to settle. Is there room around here?"