Favours are a difficult one.  Let's be honest, you're trying to come up with an idea thats not been seen before but thats not easy!  You are also trying to provide a worthwhile and memorable gift for around 120 people...on a budget.  Consider these for inspiration...

What could be more effective for that classic green / white theme than this perfect single stem of fern, a cinnamon stick and finished off beautifully with brown twine.  Spot on.  Photograph by Matthew Bishop.