First i would start with a good or decient headunit. pioneer,alpine, kenwood or so. Next thing would be a good set of speakers. And then a subwoofer and amps or amp. There are many ways of putting a system toghter. What are you looking to acheive later? Madd bass, loud mids and highs, over all balence. Your budget makes it impossiable to do a full quality system. Start with a headunit first and follow as mention.