While it's commendable that many users like yourself have been actively testing Windows 7 and reporting bugs to Microsoft, there isn't a formal or direct compensation scheme for beta testers in terms of discounts on the final version. Beta testing is usually voluntary, and users participate by choice to help improve the software for the benefit of all users.
Although there may not be a special discount specifically for beta testers, Microsoft typically incorporates feedback from testers to enhance the final version, ensuring a more stable and user-friendly product for everyone.
If there are specific programs or initiatives related to beta testing discounts, Microsoft would typically communicate that directly to the participants. It's always worth keeping an eye on official communication channels from Microsoft regarding any potential benefits or rewards for beta testers.