Fresh chicken stock is a staple in my freezer, because the store bought stock powders have so many strange ingredients and doesn't taste nearly as good. I use stock for a whole range of things, including seasoning mince meat (cook it down so that the liquid boils down), soups, stews, casseroles and risotto (a favourite of mine).

Stock is extremely easy to make and if you're not picky, you can basically make it from whatever you have in your fridge and cupboard.
The easiest stock is plain vegetable stock which contains whatever vegetables you like, although I recommend onions, celery and carrots as a base. You can even make stock with vegetable peelings. Just dump the veggies in a large pot and top up with water, bring to the boil and simmer for an hour. Done.
But I like a richer stock and my favourite is chicken stock. I used to make it with just leftover chicken bones or a carcass and veggies (and there's nothing wrong with that), but now I've found a flavourful recipe.
Ingredients:
6 - 12 chicken wings (more means more flavour)
2 onions
2 - 5 garlic cloves, bruised
1 leftover chicken carcass (optional)
1 carrot, chopped
1 celery stick, chopped
Season and roast the chicken wings in the oven. Meanwhile sauté the onion in a large pot until it starts to caramelize. Add the garlic, carrot and celery and continue to sauté until the vegetables are soft.
Add the chicken carcass (if using) and roasted wings to the pot.
Deglaze* the roasting pan with water or simply scrape out as much of the sauces and bits into the pot and top up the pot with more water.
Bring the stock to a boil, reduce the heat, cover and leave to simmer for up to 2 hours.
Once done, strain through a sieve lined with cheesecloth or muslin and discard solids.
Let the stock cool before placing it in the refrigerator. The fat with solidify on top and make it easy to scoop out before transferring to freezer bags or containers. Remember to mark the containers clearly.
To make beef stock, substitute the chicken wings and carcass with beef soup bones or bone-in stewing beef.
The great thing about stock is that you can play around with the ingredients until you find a combination that you love, but you can also whip it up with whatever you have on hand, making it cheap and easy to make and always have fresh stock on hand.
You can also season stock the way you like: salt, pepper, bay leaves, rosemary, oregano, etc. Some people prefer not to season stock at all so that they can play around with the seasoning of the dish they use it in eventually. I always season mine with salt and pepper.
*Deglazing: heat the pan and add some liquid (water, wine, etc) while stirring and scraping to loosen all the fragrant pieces and juices left in the pan.