I think it would be perfectly fair to offer a discounted price to those who bought TextMate 1.0 (as opposed to free). That's a pretty fair thing to do IMHO. Many others said it, but if you are shelling out all the big bucks to buy a Mac, spending a few more bucks on an outstanding piece of software. It is a good way to show your support to the developer and make him continue sending out updates.
Just imagine the scenario where he does offer it for free, makes virtually no profit, and then ends up quitting support for TextMate 2 (as in making bug fixes, features, etc) because he can't afford to just live off of doing that. We all lose in that scenario.
I'm a student with lots of debt, but I will buy TextMate 2 full price because it's a good investment. Even if he does offer it for free, it would be a great gesture to buy it anyway or at least open up a donation thing for him.
Can't wait for its release!