Not that I want a coffee mug, because well I don't drink coffee...
In my opinion, helping out a charity in actually doing something is sometimes worth more than the money. There are plenty of people who will give money but very few who get their hands dirty doing something.
I am the Treasurer and serve on the Board of a local group that produces musicals for children. Every year I work on the script, I keep the books, I sometimes sing and less times act, I help raise funds and I write a few checks out of my personal account. At the end of the every show I get to see the kids and their parents walk by and talk about how much they loved the show and how much fun they had. Those smiles and comments make everything I do worthwhile. Knowing that I have done something that has touched someone's life is worth much more than writing some check to some charity no matter how good their works are.
I do applaud your effort though. Its nice to see people offering to fill needs in exchange for helping out a charity.