Other than using little trays filled with water and placed in the freezer, is there any way of getting cubed or crushed ice without too much cost ?

You can add an icemaker for about $125-$150

Thanks for for response, Esquire1, but the old fridge I've got in my shed didn't cost much more than $200 ! I guess I'll just have to get used to paying that or putting up with the old trays.