OK, so I'm following the trend and have started a Teachers Notebook shop! It does seem REALLY good for sellers since once you add up your TpT monthly fee (annual charge divided by 12) PLUS their commission, it ends up costing more than the Teachers Notebook monthly fee. So if you sell, you should sign up - there is a link to the side of my blog.
If you buy, than it doesn't matter where you buy from because the products cost the same! So really, it's a win-win and you are helping your favourite sellers! You can visit my Teachers Notebook shop by clicking the button here or in my sidebar. I've only got a few items listed at the moment, but more will be added soon.