h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

These aren't always cheaper. It's often just a marketting ploy to get you to spend money on the supermarkets.

Value ranges are usually a bit better, but not always.

One of the best thing to safe money food wise, is learn to cook from scratch. It's possible to go to the market and,if you shop wisely, get ingredients and make batches of food. If you're cooking for two, make enough for four and that's your dinner for the following day sorted out.

I agree with this a major saving and also in conjunction work out in advance a balanced diet so you know what you actually require to eat and if possible even make it yourself it may even prove cheaper still.

Checkout the bogof offers - if it's something non-perishable that you regularly use & have room to store, probably worth getting. However, this may tempt you to use more of the product because you know you have plenty, so be restrained in use!

Join a wholesale warehouse like I did. My workplace offers membership of the warehouse, and certain things you can buy in bulk earlier in the year, such as washing up liquid, bleach, soap, rice, tinned food, etc. You can save substantial amounts of money on this sort of produce aqnd the outlay has gone out earlier when you have the cash.
Also, during Christmas, these places tend to do alcohol and seasonal foods a lot cheaper. If you want to buy a lot of perishable foodstuffs, then get together with a few friends and stock up on vegetables, fruit and meat.
Getting membership of such a warehouse might be difficult, but often you might find that if you work for local government or a big company, that it's a lot easier.

get down to weigh and buy (or whatever theyre called) and buy dry good loose.

I keep all my pasta in an old sweety jar (bought from the sweet shop for 10p) and I used to get all my pasta from weigh and buy for next to nothing (although they don't do organic in my shop so I've gone back to the supermarket again now )