In the picture: gronola bars, fresh bread, and 10 half-baked personal sized pizza crusts.
Not in the picture: loose gronola
My frugal tip for today is to bake in batches. As you can see from above, this day I baked a number of things. The loose gronola was first as it takes a low tempature. Then I had to plan out when the bread and pizza dough would get done rising and baked them one after the other. Next was the gronola bars, which I was mixing up as the pizzas were baking. Then I turned around and made a couple of those pizzas for dinner that night. All in all, my oven was probably on for 3 hours. But, there was no preheating for each item. I'd get one done and in would go the next one.
Also remember, during the winter, do your baking in the morning. That way it heats your house. In the summer, do your baking in the evening so you aren't running the A/C to cool off the house again. And when you are done baking in the winter, leave the oven door cracked and you'll have a toasty kitchen to do your clean up in!