I went to a second hand shop and got a 400L freezer for $200. In this I set 20L blocks using a square container/bucket. Some I leave whole and some I break up with a hammer and screw driver and bag long before a trip. So there is a mix of block and crushed. I like to add a little bit of crushed ice out of the bag as the fish go in and one or two big blocks to a 200L box. If the 20L blocks are old (over 6 weeks) there is no problems getting 5 days. All old bait goes in this freezer and gets chopped up for the next trip. Have had the freezer for 10 years now so all my ice in that time has come to $200 and a bit of my time. That would even make a new freezer cheep compared to what you can spend on ice over that time.
Regards
Dwane