I've done PL monthly for 2013 and 2014, and I think you kind of have to ask yourself a few questions before you decide what supplies to get/hoard. Do you want to do monthly or weekly, or other? (Keep in mind that one year will fill at least 1-2 albums! One of the pitfalls for me.) Do you want PL to take the place of some of your traditional pages, or in addition? What kinds of things do you want to record there? Do you want the album to have a cohesive look in the end?
For me, I started PL because I make 100% digital layouts, but I make cards. I wanted a place to save the cute little bits and bobs that I collect for cards and the ephemera from daily life. I was also feeling left out when I looked at blogs etc, lol. I'm horrible about printing my pages/photos, so PL forces me to print at least 7/month and have something tangible for my family to see. It also gets my handwriting out there, since I use fonts for my page journaling.
As for supplies, the first year I used BH grid cards and decorated with stuff from my card stash, and I LOVE that book. I think if I had time, I could do it like that every year. But, I needed a list to give to my secret Santa last year, so I asked for PL Honey edition and it worked out. We added a kid this year. With the core kit, I don't have to dedicate any time to get the "framework" of the album together, and if I want to/have time to add embellishments, I can (I don't. Ha).
PL is so flexible, it's freaky. Good luck! Hope that helps and that I didnt just overwhelm you! Any questions, just ask