Their initiation into adulthood is a big deal - as well as a big feast and new status, I believe they'll get clan tattoos, the benefits of clan Rune magic, the clan wyter, and possible lay membership of another cult.
If you want to give them a bit of loot, but in a culturally rooted way, then perhaps at the feast they're also gifted a weapon or piece of armour (or item suited to their parental occupation, with potential fun use in adventure) by their family or the clan chief. Or they get their heirloom (if you've not given it during charcter creation).
Using their parental occupation