In that price range, you are going to limit yourself to units that are stand alone and only have 1 card slot.
If you are wanting to have a unit at the bow and console, it is nice to be able to interconnect them.....Problem is, to get a unit with 2 card slots and the ability to connect via Ethernet you are going to be spending closer to $1000.....See the Humminbird 899.
The other option would be to buy used......I personally would go for a used 798, 788, or 898 before I would go with new units that won't network. I would want a SI capable unit at the console....You could make the bow unit a DI if you want to get a unit with a dedicated DI crystal.

If you want new and don't care about networking check out the new Humminbird Helix models, you can get a LOT of bang for your buck with them.

Also call Brian with BBG for better pricing and support.