the price difference between two shops eight blocks apart is insane

two places. eight blocks. same afternoon, same thing, and the gap was big enough that i went back and checked i had not misread the tag. i had not. i keep being told this is rent, taxes, volume, whatever. maybe. but eight blocks is the same rent, roughly the same everything, and the difference was not small change. at some point the explanation has to be that one of them just decided it could. what i want to know is whether this is a city thing or if the rest of you see the same spread. no names in here, just numbers, i am not trying to start anything.