You would be hard pressed to get better unit for the money than one of the Bird Helix units. Pick one with 2D, SI and DI in a size that fits your budget, and you will be set.
I double down on this comment. Side Imaging is an incredibly valuable tool when you learn how
to use it. If you go Helix other than a MEGA unit then be sure and make use of the trade up
program that Humminbird offers on the HD transducer. I speak from personal experience. The HD
transducer is worth the extra $90. PM me if you have any questions.