Evap is as cheap as chips, as we say over here (meaning it doesn't cost much - two nations divided by a common language
).
You could use the rest for sauces (eg cheese) or in rice pudding or other milk-based puddings.
I drink my coffee black but have friends who find evap delicious in their's. (It's pretty grim in tea!).
You could have it on tinned fruit as a dessert. Good on porridge or other breakfast cereal too.
My cat has a bit of a thing for it but only gets a teaspoon on special occasions as it's not really good for her.
I'v never frozen it but you could try.
(NB Evapourated milk is not the same as condensed milk)