You can get a decent little unit from Lowrance,Humminbird or Garmin for around a 100.00 or less. Will show the bottom and brush piles. Will help locate bait fish schools. You can find and follow creek channels. Basically all you need to get started. Save as much as you can and use it for other thing you will eventually need. Or put up the difference between that and your max budget. Add a few bucks every payday or so and down the road if you see the need you will have the money for a bigger unit.
Proud Member of Team Geezer
Charlie Weaver USN/ENC 1965-1979