Although only a TextMate newbie, I would be happy to pay for an upgrade to version 2.
That said, I can imagine a purchase page that allowed upgraders to choose from a number of possible "donation" amounts--say, via the sort of pull-down menu you get when paying for music at http:// Magnatune.com. You could then bury the option to Upgrade for Free somewhere deep on the page or on another page, so that it's an option for the needy.
I would also love to contribute a few beers to bundle developers-- perhaps via a similar system or a "checkbox" list.
Thanks to everyone who's contributed to this vibrant community!