Ioncube if php
Encrypting isn't free. Ioncube offers an online encrypter so you don't have to buy the actual program. I think it cost me 10 or 20 cents?
If you absolutely can't pay, create a variable depth encoding scheme using rot13, gzip, eval and other encoding schemes. They're not very effective if the people you sell to want the code because I can create the reverse of what you did in about 2 minutes.
I tried that, and there is a test version that last 8 hours, so I tried it to see if it works, I put the encoded codes on my site and view the page, it shows the page fine but when I view the source code, it shows all the unencoded codes, am I doing something wrong ?
Thanks