Never tried the Ice products but I consider spray wax more as a kind of top-up wax than a full LSP.
I prefer to put on a base layer of paste wax, then top up with a spray wax every couple of weeks to maintain.
To save a few pennies have a look at Dodo juice panel pots - about £6
I have done my whole car with one coat and hardly indented the top surface of the pot, reckon it would do about 12 coats in total, enough to last a while.
Cheapest I have found with p&p : http://www.performancemotorcare.com/...Dpanel%2520pot