It's a pay what you want sale, so you can pay whatever amount you want. Yeah, it'd be great if you donate enough to give them some amount of money after paypal fees, but I don't think we need all this debate about "you must pay $x or you're a cheap bastard". Pay whatever you'd like. Even a dollar is better than nothing, and you can always go back and give more money to the developers or charities later if you find out the games are more awesome than you thought and feel like they deserve more money from you.
So, perhaps onward to more interesting discussion of the games and the deal, and less of scrutinizing our fellow cags?
I don't know if anyone else tried installing in linux, but I thought I'd share a few tips for those that are interested. The deb files are pretty straight forward, but I encountered an error with Revenge of the Titans, which is fixed by running "sudo mkdir -p /opt/revengeofthetitans/full_length_music/" first. As for the non-debs, if you run them with "sudo" and select to install in the directory that's not in your home directory, it will add items to your menu to launch the games. Overall, I am impressed with the multi-platform support.