QFT.
I don't mind "blowing" $3.95, $6.00, or even $9.95 on a PDF I think will be useful. I try to read reviews of stuff before I buy, but if all it costs me is 4 or so dollars, I'm happy to spend a few sheckels. Heck, if I don't like it, I'll keep it because hey you never know how my tastes...