"Phone cases are not car tires."
Because $2 is the advertised price, not the actual cost.
Like $19 CanadianTire phone cables, you can find better/cheaper ones, anywhere.
Tempered Glass protector is a different story. I read somewhere there are different methods of making the glass/plastic and some can actually protect the screen from impact. That's why cheap ones are $3 each on ebay, shipping from Asia included.
A friend of mine tried several protectors from Amazon (CAD 9 ~ 20), dropped the Samsung several times and only few survived. Same phone, same impact angle / height. Make just luck.