I would most certainly buy it, as Slick is a lovely extension and the only existing full-tabbed RSS client for Chrome. My life would be a little more painful without it, and an upgrade is welcome. However, I believe most users would be unwilling to try a paid extension, and given the surprisingly small userbase for Slick, and surprisingly large amount of crappy other RSS extensions, I wouldn't expect many purchases. A trial version would be great for getting people onto the train, if that's possible in Chrome Store. An alternate way could be to promote donations, by posting related info on the app page in Chrome Store, in this group (a sticky message), and on the options page in Slick. I love the work you do, and I hope others could show appreciation, too.