It is ideal to place advertisements for the sale of complete car kits here.
Or, for example, you are selling machine kits for Ford, and you have several machine kits for Renault. This is not your topic and you are ready to give them all at a special price (cheaper), but all at once.
Or you have a few parts left for some brand of car, and you are ready to give everything at once, by offering the buyer a good price. Or maybe on the wing, bumper and hood separately you have a price of X rubles, but if they are taken all at once, then you agree to the 0.8X price.