Probably a really obvious question?

I have managed to find out that my stereo and wing mirrors wouldn't operate due to a blown 15amp fuse by taking one out for something else and using that one in the slot, just wanted to know where i get a new one from, are they mazda items , i have seen them in other cheapy shops but they look a bit different to the one i have taken out so not sure if they will fit?
Any help greatfully appreciated,
PS Can i purchase a set of fuses for future problems from anywhere?