I can tell you from personal experience that 13" bag is great. Totally worth $4. I have several. I have one in each car that holds make-shift emergency kits. I also have one that will hold a lot of common tools as my go-to bag when I need to do routine maintenence around the house.
These are not heavy duty bags, nor are they advertised as such. They are good bags for the price.
"Before you diagnose yourself with depression or low self-esteem, first make sure that you are not, in fact, simply surrounded by a$$holes." ~William Gibson