Templates are definitely an easy way to make this, or you could use any easy ebook cover creator. If you will be doing image manipulation/creation/editing on your own then photoshop is the best tool in my opinion. You still need basic design skills, so if you don't have any of these it's often best to get a more professional ebook cover made by a pro.
If all you need is mediocre quality, I believe anyone can use a simple PSD file with photoshop and make a respectable looking cover.