What was the prize for the best storyteller among the pilgrims in The Canterbury Tales?

The innkeeper of the Tabard Inn is absolutely delighted to have his hostelry patronized by so many clients, most of them quite well-heeled. In medieval times, pilgrimages were big business, not just for religious houses or hawkers of relics, but for anyone needing to cater for the needs of pilgrims. The journey from London to Canterbury was quite an arduous one in those days; pilgrims needed to be fed, watered and rested—their horses too. So we can well imagine how lucrative the pilgrimage is to the Tabard's innkeeper.
In gratitude for his windfall, the innkeeper offers a lavish prize for the best story-teller among the pilgrims: a feast in their honor once they have returned to the Tabard from Canterbury.