if you still have green tomatoes in your garden, you don´t have to throw them away. save them from frost and even though you can´t eat them as they are, because they are toxic as long as they are raw, there are some things you can do. you can cook green tomato chutney or, as my parents always do, turn the green tomatoes into red ones.
all you need is an empty shoe box or any other air-permeable carton, a chilly dark place and a little bit of patience. put the tomatoes into the shoe box and make sure that they remain without any light. after one or two weeks you will see that they turn red. of course they will not be as sweet and aromatic as they have been in summer, but still better than those you can currently buy in the supermarket.