Basic portable Humminbird unit + ice transducer and you're set.
If you want fancier features like side or down imaging, gps, large screen, etc, look to spend more. For entry-level use, I did not miss them.
When ice fishing, it's a depth finder, a fish finder, and a lure tracker. You can play fish accordingly.
In the summer in deep water, you lose the ability to track your lure accurately due to currents. Thus, it becomes more of a depth finder and structure reader. You can find depth, thermocline, structure, bottom contour, drop offs, and perhaps springs.
I've successfully honed in on fish in around 30 fow in the summer, this was in a deep river, in a section with minimal current. They ended up being smallmouths. But don't expect to track and follow lakers in the summer like you do on the ice. Learn where fish will be holding in relation to wind direction, season, etc.
The battery with the Humminbird unit lasts all day, I've never had it run out, even in winter.
