I like that idea, and it inspired me to remind people to please also consider just giving "thanks", too.
Sure, I'd love a song or a small ebook (and maybe I should set up a wishlist), but I also love getting an email saying thanks, particularly when it is from someone I don't already know telling me that they like a module I released to CPAN or telling me how they are using my code to solve some problem they have. Email is cheap, but still has huge impact.
Perl is a community built on altruism. Don't forget to say thank you!