In my final year of University I decided to write some basic shareware that was helpful in creating your own custom theme for the recently-new Windows 95. After completing the app I put it out there to the shareware community.
I attached a note to the program asking for $20 if you liked it. I was very clear with the program though that there were no additional benefits to registering other than a clean karma. The program was fully functional from day 1 and payment though highly appreciated was not necessary. Being the poor student that I was I also offered a great incentive to people - instead of sending me $20 they could photocopy $20 and just send me the scan. Yes, being a 20something about to graduate encouraged me to ask for money but I was still too scared to jump in fully.
The crazy thing was that I started getting cheques from all over the world - and received some really cool scans of foreign currency that I hung on the walls as art. I even had the strange experience of receiving a note from somebody who lived in the apartment across from me who found the program and wanted to thank me (he was a student too so no money but having somebody at my University send me a thank you was even better than a cheque would have been).
I'm glad I wrote the software and put it out there. Even though I didn't make enough to retire I had finally realized that working for yourself can be intensely rewarding in many ways.
(I also learned a valuable lesson that even big companies can have problems writing cheques sometimes - I had one very well known software company send me some free games rather than a cheque.)