Had some parts that I was trading for ammo. Trader offered 500 rounds of wolf and tulammo (parts were really worth more than that, but I wasnt using the parts in the near future) and called it a deal.
After, he comes back saying he only has 460 rounds and offers bow parts as compensation. Not really fair in my eyes, so I told him the deal was 500. He ended up going out of his way to not only keep up his end of the deal, but went beyond it by 20 rounds.