I wouldn't buy a toaster oven. A toaster oven is clutter when you have a perfectly good oven that does everything at toaster oven does. Living simply, I think, means making do with what you have. You have an oven. Make do. 
I'm guessing you have been using a toaster oven at your last place, and that's why it even came up at all? If you want one, get one, but I wouldn't rush it. You might find that you don't need it.
I think whatever you end up missing after a few weeks on your own will be the things you want to buy.
I'm kinda jealous. But, I'm in that "almost done with childrearing" stage, and I've never ever lived on my own (without kids).
Karen
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insidious ungovernable cardboard