need help on selecting fish finder
i am a noob when it comes to lake fishin. i have a 14 ' jon boat that is a decent boat .. i was wondering i am wanting to get into fishing the corp piles on the big O in OKlahoma. what would be my best route to go on some electronics on a limited budget of around 300. what unit can get me on the fish with gps and sonar to locate the piles.i do have the navionics app for the i phone and you can input coordinates on it . dont know if i could get by with that to get me close and maybe just good sonar. the only thing is im not sure the difference between the chartplotter and gps any input is gold for me thanks.