I have a Lowrance gps for sale. This is the same as the lowrance xtr polaris gps less the 2d topo maps.
http://www.lowrance.com/en-US/Products/Chartplotter/HDS5m-en-us.aspx
$450 shipped.
http://www.lowrance.com/en-US/Products/Chartplotter/HDS5m-en-us.aspx
$450 shipped.