Note: all downloads are trials. To get the full version of a specific software, you have to buy it.
Also, when creating a banner or logo online, it might not look exactly the way you wanted it to look or it wont be as good as you wanted it to be. Which is why I'd recommend to download or buy Photoshop, paint.net or something like that - learn to use it well enough and you'll be able to create great banners yourself. Just a tip for those who might not like the online banner/logo creators.