Teachers Pay Teachers is a marketplace for educators who wish to sell their creations. It allows educators to buy, sell and share their original resources and is a great resource to build teacher community and support.
Having used this a couple of times, please be careful and make sure that you take a close look at things before purchasing. There are free things on the site as well. While most free offers are not of the best quality, you will stumble across a a really high quality freebie every once in awhile.