I wash and reuse freezer bags, except the ones that had chicken in them. I know some people turn the bags inside out to dry. I don't do this because I always seem to tear the ends of the "zippers". What I do is take a section of a "select-a-size" paper towel, fold it in half and put it in the bag, then press the bag flat. You can zip the bag shut if you want to, but this is not necessary.
Don't throw away your cereal bags that contain cereal, they make great freezer bags when you run out of store bought ones or just to save money. Or you can use them with Dollar Store freezer bags for extra protection from freezer burn.
I save the waxed liner that dry cereal comes in. I wash it really well and then let it air dry. Then I use it as a large freezer bag. It's free, so don't waste it by throwing it away.
To save money on freezer bags, put food in sandwich bags, then put several sandwich bags in one large freezer bag.