Vinegar is pretty cheap and there are tons of uses for it at home.
Drain & Disposal Cleaner - This is one of my favorite ways to use vinegar. When I am cleaning my kitchen I pour baking soda down both sides of my sink, add some vinegar so it will bubble and leave it to work. I let it work while I clean my cabinets. Then I come back and run hot water through the sink while running the disposal.
Cleaning the dishwasher - About once a month I like to fill the soap dispenser of my dishwasher with vinegar and run the system. This cleans the inside of the dishwasher, the racks and the heating element.
Eye glasses - All three of my guys wear glasses and vinegar is the perfect things to clean the lenses. No smears and it won't discolor the lenses.
Sponge sanitizer - I have a "thing" about sponges. They are just yuck to me, but if you use them it is best to sanitize them. Soak them overnight in a bowl of vinegar. The next morning squeeze it out and it will be refreshed and ready to use.
Crayon remover - Test this in a small area before you go crazy, but the next time your Picasso creates a work of art on the wall grab your camera and take a pic, then grab a tooth brush and some vinegar and watch it disappear.
Fruit & Vegetable Wash - Keep a bottle of equal parts water and vinegar to wash your fruits and vegetables before you eat them.
Get rid of Fruit Flies - Pour a cup of apple cider vinegar into a jar or small bowl. Add a couple drops of dish soap to the jar. Cover the container with plastic wrap, and poke a few small holes in the wrap. Place in the area where you've seen the fruit flies, and wait for the trap to do its job.
Bye Bye Rust - Apply undiluted white vinegar to the rust by spraying or dabbing it on (if the object is large), or by submerging the rusted object in vinegar (if the object is small). Allow the vinegar to soak in for 30 minutes. Then, rinse the object off; and dry thoroughly. Repeat the process, if rust remains.
Flea Repellent - Mix equal parts white vinegar and water together in a spray bottle, and apply the mixture directly to your pet's coat. Finish by working it in with your hands, and your pet is protected from those pesky fleas. Fleas HATE the smell and taste of vinegar and will avoid it and this is safer for your pet.