If you have a well stocked kitchen, you should be able to come up with these ingredients.
Assorted spices. Yellow capped, repurposed jar contains dry mustard.
Whirl all together in the food processor and bingo! French dressing! No need to buy a bottle on "sale" for $2 if you are lucky. This costs a lot less, and you can control the ingredients.
Now decanted into a repurposed, quart EVOO square bottle that fits nicely in the fridge door, I made a quick label out of scrap paper. While not a quart of dressing, you can see that most of the bottle was filled.