[morepower71]

Most of the difference will be build materials and power handling. The really cheap speakers are not going to last you long. Usually those are thin paper cones and very thin foam surrounds and if they get even a tiny bit wet they disintegrate. $100 for a set of speakers is about your best bang for the buck range. But I wouldn't go over that price unless you are running amps for all speakers and using a high quality headunit and going to tune the system because you wont really notice the difference unless you know what you are listening for.