They are nice, but you have to ask yourself what you really want or need. And, also check to see if you need to purchase
the transducer separately (which seems likely). And another thing is to check to see if you need one of the sonar boxes to decode the transducer to give you your depth.
I went through the same with my Standard Horizon stuff. Bought the transducer thinking it would plug
into the back of the unit, but turns out I needed the fish finder box anyway, because it has to decode the transducer signal into something the plotter could read. So that $1300 chart plotter, could very easily run you into more like $1800 by the time you're said and done. Not counting the chart chip, though I see there's a $200 rebate back with that if you get them both, so it's only an extra $100 at the end of the day. Still, you're quite a bit above your budget
from 4-600 at that point. Are they nice? Very. Just decide if it's going to be more than what you need, or if it's worth it to you to invest into that now, for the future use.
To answer your transducer question, btw... it depends on how comfortable you are with the various installation
options. There's the thru-hull design, which requires you to either replace an existing one with a new one for the unit, or drill a new hole and install the new one. Ideally would require hauling the boat, it's risky to do that without a haul. Doable yes, but... not for the faint of heart.
Or, there are in-hull designs, like this:
They have a ring that mounts inside the hull
, under a seat, locker, or somewhere ideally along the front of the keel
somewhere, and as close to center as possible, but wherever. That ring is then filled with a fluid (a few options) and the transducer locks into place. That saves any holes in the boat, can still be quite effective, and the hardest part is just where to put it, and how to run the wires.
From what it looks like, the Garmin would have to go through a Sonar Module for that. And they are $500 + on WM. I would definitely get a full quote from the salesman, who seems like he may have left out a few required bits that are going to rack your total up.
ALLLLL that aside, there are still plenty of them out there, like emcmia mentioned, that are smaller, 4.3 - 5 inch models, that come with transducer and chartplotting capability for where your original budget sits, or a little higher. Most of the time they're listed on the sites as fishfinders/chartplotters, so look at the fishfinder
section, and see what you find. Even without using it for fishing
, that is what's adding the depth capability and most will add charts too.
For example, 5" screen, including transducer and free (after rebate) maps for it. Not too shabby. Lots of options to explore, don't let the guy talk you into more than you, a) want/need and b) need to spend.