Everything found on this site is and always will be free. I am a big open source fan boy, and feel this is the best way to give what little I can back to community at large. It's not much, but I am trying to do my part. However, if you still feel inclined to be gracious, there are a few ways you help out.
I am always looking for improvements/testing/feedback done on any of my public projects. I try to have all my projects have little to no setup, so you can do a quick five minute run through and throw improvement suggestions my way.
Amazon Wish List
I tend to keep a small list of books that would be fun to have, but not really something I need on this list. It would be insanely cool if you had enough spare cash to send one of these my way. If you know of something that's not on this list, shoot me the suggestion and I'll add it to my list if it fits me right.
Beer Fund (Paypal)
If none of the above fit your persona, there is always cold hard cash. I can't say I will use it in an appropriate manner, but I can tell you I will have fun with it.
A big thank you for any help you are able to provide. Big and small, it goes a long way in keeping my motivation in these projects.