I have a very simple problem, and I'd like to find a simple solution that won't cause me 60 bucks. I'd like to be able to put page numbers on PDF's. A script, a plugin, an application... ANYTHING that can do it would work. I have one requirement: I don't want to spend 50 dollars just for this feature. The open source Skim.app is absolutely incredible. I relied it on heavily when writing my thesis. So I've already got a wonderful tool to mark up PDF's. And I don't want to spend 60 dollars on a copy of PDF Pen when the only function I need is page numbering. I'm willing to pay, but I'd really rather not pay more than 10 or 15 dollars for this seemingly simple feature. So... any suggestions?