HDS7 Gen3 and NSS7 Evo2 around $600

Top of the line fishfinders are going for about half the price they were when new.  They've lowered the prices of the older models since the release of the newer Lowrance HDS Carbon and Simrad Nss evo3 series.

HDS7 and Simrad nss7 evo2 can be found for around 600 w/o transducer if you look hard but I'm sure it won't last long

$619 HDS7 gen3, free shipping, no tax

http://www.russellmarineproducts.com/product-p/low00011784001.htm