Does it really helpful to design a flag for my shop?

I learned that there is something called beach flags design by free on the Internet .
It really beautiful and attractive. However does any one really used that thing ? I want to buy one on a free design beach flag company – . After I asked the price , it is really cheap and designed for free. They send me a simple. But I don’t know the affect of the flag. Does it really helpful to my business? Any one can help me ?