My old 582 has a dodgy transducer port so I've recently got a new Furuno GP-1971F to meet my needs.

The old 582 paired with a 600W transducer worked just fine for me for about 15 years of service (100's of Dhuies).
I could easily see my braid and jigs on the screen in 25m of water and it produced many quality fish in <100m (we found plenty of Reds in 70m in Exmouth, struggled a little in 100m+, but no doubt would have been ok with a 1kW transducer).

If you want a cheap solution for fish finding and the 582 is in the $100's then good.
If you want the benefits that a new combo can provide, like new chartplotting maps and data and being able to goto good soundings then you may need to spend the money.
So far, I'm happy with my new Furuno GP-1971F (they do a 7" model, GP-1871F, for less than $1,700 +C-Map costs) but I still haven't yet got it working as well as my old 582 in regards to sounding.

I know that there are some really great sounders out in the market that will run rings around the old 582 but for what I paid for it some years back and the results it produces I'm quite happy with the performance it produces, I guess it comes down to how many dollars you are prepared to spend and what results you expect from older technology.

 I ended up getting a 627, brand new still in the box with a new P66. Got it for about $800. Probably paid too much, but I figured I am getting an awesome sounder for a lot less than the $1900 for the Simrad. It will shit all over my Lowrance which now becomes my chart plotter.