I was recently speaking with a friend who was complaining that everything was always sticking to her cheap cookie tins. I told her about parchment paper. This paper is like magic! Nothing will stick to it and it doesn't ruin the cookie tins resulting in less clean up. The amount of time and hassle I have saved has made this more than worthwhile.
Since I started using parchment paper a few years ago, I have not looked back! I use it for all my baking and even for things like chicken, fish, etc. that go in the oven.
If you haven't tried parchment paper yet, I highly recommend it.