Whilst I don't condone cracking IBrowse there really is no reason in this time of free domain registration and advertising free website hosting and free paypal e-commerce HTML code for buttons.
1. Register a domain
2. Write a simple website.
3. Stick PayPal buy it now buttons on site
4. When you receive payment reply to purchasers email with a working key
1-3 would take half a day at most and 30 minutes if you don't care how smart your website looks. It's not rocket science, and it's a bit dumb not to do it. Costs you nothing more than 3.7% PayPal commission too, so the only reason is nobody bothered to do this.
Why turn away customers wanting a simple key to activate demo software when you can automate 90% of it and have it out there in the world of commerce for ZERO cost?