Before I got my stone, I would use a cookie sheet, upside down. No need to preheat – it’s thin enough to heat up quickly in a hot oven.
For days I don’t want to run the oven (with a stone), I use the grill. I roll the dough out on parchment paper, take it out to the grill, flip the crust onto the grill (so the parchment is on top and I can peel it off), and grill it for a couple minutes. then I bring it inside, add my sauce and toppings, and take it back to the grill to finish cooking. I prefer doing it this way over topping first and cooking because we don’t like soggy crust in the middle. Parbaking (pargrilling?) it eliminates that.