I'm not on a fixed income yet, but I'm not working at the moment so it kind of feels that way. In the spirit of saving a buck here and there, I have decided to repurpose things I buy and don't like. For instance, we all buy conditioner. Don't like it on your hair? Use it on your gorgeous bod in the shower. Shampoo too drying? Use it to shave your legs. Memo pads? Turn them over and use both sides. Facial moisturizer too oily? Use it on your hands and feet. Of course, you can always return this stuff, but I try to be a good sport.
Food can be repurposed as well. Cats don't like the dry food? Screw em. Just kidding. You can use cat food and/or kitty litter to get your car out of an icy driveway. Expensive, but hey, if they're not eating it— and if you want to get really cheap, use their hair to stuff needlepoint pillows. They'll hate that.
There's an off-brand use for everything. Mayo as hair conditioner, sexual lubricant instead of WD 40, olive oil for your complexion, etc. Age has some benefits. After years of retail therapy we have lots of crap around the house. If all else fails, use it to shave your legs.