Make a donation
If you find the program useful and want to contribute to the project, you can make a donation to my Paypal account. All money received goes into the project. They might pay for the web space that I rent or pay for the domain name. If I get enough I might buy a component.
Note that you do not need a PayPal account to make a donation to my PayPal account. You can use a credit card, and sometimes even a direct bank transfer. (look for the text-link "Don't have a PayPal account?" at the bottom-right after you click a donation button below and arrive at the donation page)
If you are using the program to create a commercial product (e.g. a web site) you really should donate a small sum.