The teeth and fingerbones of holy men and more
The Pool of (add the name of the God or Goddess of your choice) is well known as one of the greatest holy places of the world. It is said to be full of piles of gold and jewels, a place where wishes are granted, wounds are healed, prophets have dreams that come true, and suspected criminals are fairly judged. Pilgrims from the other end of the world have been known to travel for more then a year, braving the perils of disease, brigands and bad weather, just to reach it's holy waters.
Five men are herding fifteen horses down the road. They won't be very talkative, but are willing to sell a horse, or more horses if the heroes are interested. These men are horse thieves. They are already sought by regional militiamen. Anyone with a stolen horse (all are marked) may get into trouble. If found guilty, horse thieves face prison or even a hanging execution. Similar thefts have happened only a month before, and a reward is offered.