Treasure Yeti Lunchbox?

Sorry if this is too late of a response. Your lunch box prize is simply 1 thousand coins and it gets added to your coins after you beat the level. It's worth mentioning that you have to kill the yeti, pick up his lunchbox and complete the level for the prize to be rewarded. All you get is a thousand coins there is no other prizes from yetis. Hope this answered your question.