We recently started using our washer for greywater. It saved us ALOT of money watering the roses through our dry Texas summer. However, our washer started running out all the water instead of holding it and washing the clothes. We thought the washer had just killed over but after researching it on the internet we found that it was our greywater set up. We had just taken the drain hose and ran it out to fill buckets not realizing that it had to remain up at a certain height in order for the valves inside to work properly and recognize when the tub was full. Once we put it back up at the proper height it worked perfectly. Greywater from the washer is an easy inexpensive way to conserve and reuse (and save lots of money) just be aware of this potential problem when setting up your greywater system.
A washer drain must discharge to a vented secondary drain in order to prevent siphoning of all the refill water. And if it is lower than the tub, it just drains ALL the water out of the tub, used or not.
Using grey water ( all except kitchen sink garbage water) for re-use as toilet flush water and irrigation is the only consciable way to manage water use, cheap or not.
And, cheap or not, good fresh water is limited.