Raspi-Sump and hcsr04sensor are free to use and always will be. I expect no payment for these programs and am happy when others can make use of them. I have had people ask me if they could donate a small amount for their use. While this is certainly not required I appreciate your generosity. I will probably just use it to buy more Raspberry Pi's. Also, please include your email address so that I can thank you personally.
Thank you to everyone that has made publishing these programs such a satisfying experience for me over the past couple of years. It has been interesting to see how others have used them for monitoring liquid levels and measuring distances and has been a pleasure interacting with you and supporting you in your own Raspberry Pi projects.