Edit: Well just saw that you got an elite 5x, congrats I think you'll be pleasantly surprised by the performance, i'll leave the text below in case someone else reads the post later.
Depends on what head unit you have for open water, assuming you have a unit already. If you do, I would see if you have an option for an ice ducer. You can use the regular transducer for ice but it would be a pain to get it out of the boat anyways, might as well get a spare. I've used my ice ducer for my duck boat with a piece of PVC and clamp. If you don't have a boat, I would suggest buying an ice fishing specific transducer.
I have a Humminbird 365i, ice ducer was $75, extra power cord was $10, 9 Ah battery was 20$ from cabelas. Went to a university surplus store and got a padded camera case for $5.
Normally I would suggest getting a Marcum or Vex, but my Marcum is currently in the shop and I'm fishing with the home made...so..yeah...even if you upgrade later it would be good to have a backup.
