Fishfinder.........

I am sure this topic has been discussed a lot, but let’s face it we have plenty of time on our hands these days. What are you running?
I purchased my kayak used, it came rigged for an older Lowrance with blue connectors but no fishfinder. Should I look for a used unit that would be plug and play? Or get a newer unit? I see lowrance has new units with “reveal” and auto tune which seem like good things for us who can’t or don’t want to have to tune/adjust for different waters. Those units start at $300. Just getting started is expensive on its own. Are there quality older units that would be worth looking for that would be compatable with my current wiring?  What do you all recommend?