Did you know that you can reuse your vacuum cleaner bag many times?
Just pull it out wearing gloves, go over to your compost bin (wear a dust mask if you have asthma), and pull the contents out. Then you can reuse the bag as many times as you want.
This saves on money, but wouldn't be worth it for money alone. The good thing it does is save on heaps of waste - a bag every time in the rubbish (garbage), which ends up in a landfill.