Take some form of material, stuff it with something, tie it off and hang it up!
I cut up a Halloween table cloth that was getting mangey. I made different sized squares (for mommy, daddy and baby ghosties!)
I stuffed the 'heads' with plastic bags I had been stock piling. I used my daughters cheapie hair elastics to tie them off. Next I used a hole puncher to get the string hole. I threaded some twine I had and voila! Easy peasy Halloween craft for pennies!