are you looking for something portable that you can carry around or mount to the boat for more permanent fixture? i use a humminbird pirahnamax 160, its got a dual beam, and im happy with it cause i can take it with me anywhere.. ice fishing, diff boats, ect.. it costed 161.00 at bass pro. if your looking for something more extravagant you could always go with the sonar/gps combo.. can go from around the 400-1000 range.. skies the limit when it comes to marine electronics lol. check the bass pro website or even kajiji listings for used ones if you would like to save some money.