Use a Measuring Cup
When it comes to laundry detergent, more is not better. Overusing detergent just means you'll wind up buying more, and leaves your clothing looking dingy. Look on your washing machine for what the manufacture recommends as the proper dosage, not the recommendations on the detergent bottle. And get a clear, easy-to-read measuring cup if you're a chronic over-user.
Use your measuring cup for cheap laundry boosters, too. Add a half-cup each of washing soda and borax to your loads for super-cheap, natural whitening, deodorizing, and water softening. Add a half cup of white vinegar to your rinse cycle for pennies-a-load fabric softening and static control, and ditch the expensive (and toxic) bottled fabric softeners and dryer sheets.