I'm another that uses stock from bones but I do tend to have a Marigold in the pantry just in case.
I tend to freeze my chicken carcus's (it drives Mick mad - the amount of times he has got them out and defrosted them thinking they were something else ) until I have a three or four and then I make a massive pot of stock. Then I freeze the stock, usually in plastic milk cartons (that drives Mick mad too as he thinks we have milk in the freezer.