It is a zipper coin purse, but it has straps on the back and looks like a mini backpack.
It is small - see the photos for measurements and for how the size compares to a can of soup. However, it can expand to about 1 1/2 inches and so it can hold a decent amount of coins and folded bills.
I have had this little coin purse since probably the 1990's. My daughter played with it as a backpack for her Barbie dolls!