A few interesting points in here.
Having worked in a couple of tackle shops and animal feed stores I know how much bait costs both ways.
In terms of base mixes and boilies, the tackle shops buy from the manufacturer, at cost. It's basically divide buying price by 2, then multiply by 3 and add VAT, so £6.99 tackle shop buying price worked out at £11.99 when I was there. That's not that big a profit when you consider storage, freezer, carriage, wages and handling.
It is very difficult to compete when anglers are able to buy direct from the manufacturer at cost!
I used to field test, proper field testing rather than buying at discount, and I bought non test bait at discount, but got test baits for free, if that makes sense. The test baits I gave feedback on, and gave ideas for baits I came up with. There were a couple of my own flavour blends and pop-ups added to the bait makers range, which I never had to pay for. Come to that I know that a fish in I provided a lot of bait for for anglers going which was given to me by the bait company.
I couldn't afford to pile bait in as a field tester, yet I saw some with magazine media presence really go for it.
A bulk bag of pellets from a wholesaler is around £60, around £3 per kilo, so if a tackle shop sells them you are looking at around £5 a kilo, which is why so many sell 1kg bags. I'm not sure on the price of buckets, I think I paid £10 for a bucket last year (my sea fishing bucket) from a shop, yet years ago I used to get 10kg buckets of base mix for around £72.99, the bucket was free.
@Golden Paws I don't like having loads of bait about, but I do have an advantage, Gladwells at Copdock Mill is 5minutes away, and I can buy ready prepped hemp, and 3kg buckets of pellets, or bulk sacks. Gladwells incidentally own Crafty Catcher so I can get bulk bags of Skrettings pellets or Crafty Catcher pellet buckets. I know Gladwells sell their boilie and bait range at the same price as tackleshops.
I do buy 1 or 2 kilo bags of birdfood from the supermarket and prepare at home.