I've had a couple different teacher magazine subscriptions over the years, but Mailbox magazine is by far the best one. Even though many school libraries have it, it is nice to have your own copy. If you were ever going to invest any of your hard earned money, I would suggest it be in this subscription. Their issues only come once every 2 months, but it is well worth the wait. They have tons of tips, ideas, and printables (including games, worksheets, templates, etc). They also have a "companion" website that you can use if you own a subscription. The companion website allows you to print some of the templates right from your own computer. It allows for you to create and edit their items to meet your own needs.
I look forward to my copy in the mail every two months, and I read it greedily, looking for new and fun ideas to incorporate into my classroom. While it may not quite be as entertaining as reading celebrity gossip each month (i.e. People magazine), it's almost as good. ;-)