I think 20% is good, and actually pretty high for these items. I mean once you take into consideration how much the actual cost of the item is. For example a $60 key chain probably cost Coach around $25 to make, plus they are donating like $12.. which means they're only profiting like $23. (but not really because there are alot more costs involved).
Every bit helps
(i'm saving my yogurt lids and they only donate like $1 per lid
, lol)