[Dicky]

Any one know a good one, either online or in Norfolk?  We currently put out fat balls, niger seed, peanuts, sunflower hearts and mixed seed.  The fat balls and mixed seed aren't too bad but the others can be really expensive.  Best prices I think I've seen so far have been on Amazon.

[Small Farmer]

FIL bul buys from the RSPB but I can't believe that's cheap.  We collect from GJW Titmuss but they're local to us and used to be a forum sponsor

[Fleecewife]

You can make your own fat cakes with mixed seed and fat in half a coconut shell or similar.  I think niger seed is a con - very expensive and it's just thistle seeds - we have a great crop of those  .  The claim is that goldfinches need niger, but ours eat normal mixed seed.
We get our mixed seed from the agric store at our local mart - you need to watch that you get a good selection of seed types, as cheaper mixes tend to be mostly cereal grains.
We get our peanuts from our local pet shop, partly because we like to support them, but also because their price for a whole sack is not high.
For the fancy stuff, Dobbies isn't bad, but you would probably get it cheaper online, if postage isn't too much.
 
It's great to feed the wild birds.  Between all our feeders and our growing hedges, wild bird numbers here have increased dramatically since we moved here 17 years ago 

[Rosemary]

Our local British Trust for Ornithology volunteer sells bird food to raise funds for BTO, so we buy it there. Might be worth contacting them to see if there is similar in our area and kill two birds with one stone metaphorically speaking)

[Possum]

RSPB website. They sell in small and large quantities and you know that you are getting good quality. Fast delivery.