At $7.99 to $9.99 for about one cup, you'd make your own too.
Its simple. Just pour champagne, red or white wine or cider into a wide mouthed jar or ceramic container, add Braggs apple cider vinegar and water. Cover with cheesecloth to keep out dust and fruit flies but still allow airflow. Store the container at room temperature and let it sit, undisturbed, for 1 to 3 months. The liquid will grow more cloudy, as a mother, a spongy or cloudy blob will form. The mother is formed by a friendly bacteria, Mycoderma aceti, which turns the sugar in alcohol into vinegar. You can buy a vinegar mother from a local brewery supply store or you can use Braggs Apple Cider Vinegar which is available in many grocery stores. Braggs is raw, unfiltered and unpasteurized, so it contains the mother necessary for this process to work. Most other store-bought vinegars are pasteurized, so the necessary bacteria has all been killed, so they wont work for making more vinegar.
Taste your vinegar beginning at one month. If it still tastes like champagne, its not done. Let it sit and taste it again in two weeks. Mine took two months, but most resources I checked indicate it can take up to three months. Once the vinegar tastes right to you, filter it to remove the cloudiness and any residuals from the mother and pour it into clean bottles. I like to place paper coffee filters in my funnel when filling my jars to remove any possible debris. Vinegar is shelf-stable, meaning it doesnt need to be canned or refrigerated and will keep a long, long time.
https://goodmotherdiet.com/2016/03/02/homemade-champagne-vinegar-vinaigrette/#:~:text=It%27s%20simple.,for%201%20to%203%20months.