Saving vegetable ends for soup stock

Every time I peel a carrot (mostly I buy the big 5 lb bag of whole organic carrots they are so much cheaper than the mini peeled carrots) or an onion or chop off the tops of celery I put the peels and tops in a bag in the freezer.  When the bag fills up I add some parsley, bay leaf, salt and pepper and boil it up into stock.  If I roast a chicken I'll save the bones and throw them in the pot too.  Then I jar it and store it in the fridge until I'm ready to make soup or need a splash of stock for a recipe.  How much do you pay for a box of organic stock?  And this you make with bits that would otherwise end up in the trash.  You can't get much cheaper than that.