Homemade pizza is easy, and can be quite cheap to make. What seems to scare people the most is making the crust. A basic crust is a snap (my daughters were making pizza crust when they were barely literate). It needs:
1 tablespoon (or package) of yeast
1 cup of lukewarm water
1-2 tablespoons of oil or melted margarine
1/2 to 1 teaspoon salt
a pinch of sugar
flour (2-3 cups worth)
(optional-a tiny bit of lemon juice or dried herbs)
Dissolve the yeast in the warm water in a mixing bowl. When it's dissolved, add the oil or melted margarine, then add the salt and sugar (and optional items if using them). Slowly stir in flour, probably about 2 1/2 cups worth: you may need more or less. Add until it isn't wet or too sticky, but not so much it gets dry (sounds scarey, but it really isn't). Beat in, then let it sit for a few minutes while you grease a sheet pan and make the pizza sauce. If your house is cold or drafty, it may help to put it on top of the fridge while you work covered with a dishtowel.
This dough recipe is enough for one pizza made on a normal-sized sheet pan. Put the dough on the sheet pan, get a little flour on your fingers, and pat it out until it fills the pan evenly (kids LOVE doing this if you don't want to get your fingers dirty). An option at this point is brushing a little melted butter on it if you're ok with the extra calories. Either way, now spoon sauce onto the pizza and spread it out with the back of the spoon, covering all but the bare edge at the outside. Sprinkle with cheese or add thin slices of cheese (mozarella is the classic for this, and it's relatively cheap and low fat), however much looks good to you. Add any other toppings you want.
The pizza sauce is pretty easy too, and really isn't much different from a spaghetti sauce. We use one small can of tomato sauce, one small can of tomato paste, with garlic, oregano, basil, salt, and pepper, but you can vary it to whatever appeals to you. One of my daughters likes to add a touch of paprika, and I do love her pizzas. Experiment with ingredients and sauce and crust until you get it just the way you like it.
Bake in a preheated 425F oven on a lower rack for about 15 minutes (or until the cheese is melted and beginning to brown). Let cool enough to be safe to eat, then slice and serve.
And as for my claim that this is cheap? I buy yeast in bulk rather than the little packages, so the crust costs less than $.40, the pizza sauce is about $.75, and the cheese is about $.60 to $1.20, depending on how thick we spread it. So, as little as $1.75 for fresh, homemade cheese pizza. Sometimes, but not always, kids will cheerfully eat vegetables on pizza that they won't painlessly eat otherwise, too, and most kids LOVE helping to make this (they seem to get more excited about eating things that they helped make too). I could do a really nice veggie-and-cheese pizza for about $3.
And if you're looking for cheap food for a kids' party, especially a sleep over, this is almost always a sure hit. We hosted a sleepover with young teen girls who ate close to a pizza each (plus other party food), and they hung around the kitchen, watching in fascination. Definitely the hit of the evening.