One great way to save money when sending packages is to use FREE packaging! For example, in the picture, the big box was one we ordered something from Amazon in. I kept the box and was able to re-use it.
The smaller package I got from a freebie! Yet another advantage of signing up for freebies! You get the actual free sample, often a coupon and then sometimes packaging that can be re-used!
I probably only buy packaging about half the time, because I often have a box or bubble wrap envelope lying around somewhere. Just remember to use a sharpie and thoroughly mark out any old addresses or stamps. Sometimes I just write the address on a white sheet of paper and use clear masking tape and cover any old addresses.