i'm not surte how much they are now but ion my opinion the BEST budget sounder for 70-100m would have to be the Furuno fcv 620/627 (the baby brother of the 585/587) check out the site sponsors Furuno and if you can stretch ther budget to suit you wont regret it.  cheers

 Raymarine dragonfly. Check it out !

A good monochrome sounder is far better than an average colour sounder so choose carefully. BCF had a massive run out sale (give away) of the Furuno LS-4100 selling them at $99! A transom mount transducer like the Furuno (Airmar P66) 525T-PWD would set you back around the $100 mark. We have no idea if BCF still has any stock but accorsding to their online website they do. Suggest putting a call in and bagging a bargain of a lifetime. http://www.bcf.com.au/online-store/products/Furuno-LS-4100-Fishfinder-No-Transducer.aspx?pid=125329#Cross

Some dealers are also clearing out Furuno FCV-620's which has now been replaced by the FCV-627 so again phone around and you'll probably get a great deal.

Good luck

 Thanks for the replies guys.  And like Furuno making a suggestion to find a bargain, would be easier to just recommend the lastest model such as the 627.

looking at my Garmin Echo 200 and the Furuno 4100 they both say 300W.  If I use the recommended 600W Transducer am I still only getting 300W of power?  Or is it completely seperate.

The 4100 looks very similar in specs but was thinking the transducer would likely be an upgrade.

well in your budget and a very good sounder!

http://wafishaman.com.au/content/sale-furuno-fcv-600l 

Can’t beat Furuno I have fished coral bay for 10 years now and used a Furuno gp1650wf 600w combo same sounder as the above fcv-600l but with maps

this has found me all my fish up until now

600 w on 200khz works well up to 90-100m for finding fish schools after that 50 kHz is better for finding fish only down side you must go a lot slower

the newer fcv620 are starting to come up for sale as people are starting to buy the new Fcv 627 same as the 585 to 587

both pretty much the same sounder except the difference in screen size and the 585/587 can handle 1 kw transducer where the 620/627 can only handle 600w

If it was my choice i would look for a second-hand 585 and if you cant afford a 1kw transducer just go with a 600w transducer until you can get a 1 kw

But If you can only afford the 585 the fcv 620 will do you well and get you many fish

As i have finally gone to a fcv295 with a 2 kw 200khz and just looking at some ground i have at 40 to 50 m of water i have both sounders working side by side the 2kw transducer picks up a lot more fish than the 600w of course but the difference is really noticeable so if you are looking at fishing for reds up at coral bay you have a better chance in the deeper water to find the fish with the more powerful unit

You will still see the bottom but as you go deeper the fish will not show up as easy unless in a big school

But saying this the 600w has done me really well up until now, I can sound at 40 knots and still see the bottom and where I haven’t quite got the new sounder setup properly yet only can get 15 knots at the moment so I still rely on the old sounder a lot.

Just think you spend all that money buying your boat to get you to the fishing ground

Why not give you self the best chance to find the fish a sounder is cheap investment when it comes to spending a lot in fuel bait and time It will make it all worth it in the end when you have the fish on the boat it will pay for itself

Just my opinion if it helps im no expert but every little bit of info helps

http://www.ebay.com.au/itm/Furuno-FCV585-Sounder-Fishfinder-Package-with-TM-Tri-Ducer-50-200KHZ-600W-/200900423134?pt=AU_Boat_Parts_Accessories&hash=item2ec6992dde

http://www.ebay.com.au/itm/Furuno-FCV620-Package-w-Transom-Mount-Tri-Ducer-/190454683686?pt=US_Tracking_Devices&hash=item2c57fbd826 

 Thanks Dan1

Will keep an eye out for a furuno