I just started on Christmas Eve, myself. You'll need a mandrel, 7mm bushings, blank trimming/squaring tool, super glue, a drill press, a couple basic chisels, and some slimline kits. You also need sandpaper to 600, and polish. The slimline are the cheapest, and easiest to make, so you should start off with them. They have pen assembly presses, but you can use stout quick clamps, or a drill press to start off. You also need some wood blanks, but you can make your own from scrap on hand - 1/2" x 1/2" x 5 1/2" per pen.
I think that's about it. Penn Stste Industries has quality stuff at good prices, and they have a free video to show how it's all done.