I am not sure what your question is. Are you asking how much spray paint you need for a certain project?
Are you referring to a specific project?
That depends on what you are wanting to spray and how much you can afford!
Sorry, without more information it impossible to say...................
Prices of spray paint can vary by brand and by store. You can easily see what a can of the brand you need is going to cost by searching google for the brand of spray paint.