Probably because it takes about three pints of maggots to produce about two pints of caster. The fact that turning caster properly takes a reasonable amount of time and effort also adds to the cost
down here in the rough end of Surrey, maggots are 3.30/3.50 a pint. I don't even enquire about the cost of casters, not having access to a second mortgage.
Don't get too jealous, prices up north rather depend on where you get your bait from. My usual source of maggot sells them at £3 per pint. I don't often buy casters, but I think the same source sells them at £3.80. I could travel a bit further and pay a bit less, but I'd spend more on petrol to do so. Some of the cheaper places have dismal quality bait too, which adds another layer of false economy into the equation.
You lot are tighter than a Yorkshireman's whippet's bottom in a sandstorm!
Who apart from match anglers buys pints of casters anyway? If you only want a few, just ask the guy in the shop to chuck a handful of casters in with your maggots.... for free!
If he refuses tell him you'll set your whippet on him. Works every time.
I do look at bait prices today,years ago I have bought a gallon of maggot or more for a days fishing,not today,I would say however,if you go to a premier league match,or a test match in cricket,the price of a days sport is far greater 24 quid for maggot is cheap in comparison,not something your do every week however....
A shop I use is £2.50 for maggots £3.00 for casters, I always take a 3 pint bait tub for a pint of maggots, then when get home and tip them into a pint bait tub I generally find that I need two one pint tubs, The casters are spot on a pint most times though. I bought some in the Banbury area once, only wanted half a pint, when it came to pay I mentioned I had asked for half a pint, the reply was that is what I have got.
I buy more casters than maggots. I pay £3.25 for casters, they are available cheaper. Trouble is the cheaper casters locally to me are of a poor quality.
One thing that ruins casters is when they are kept in water to prevent them from turning. Water makes for a soft shell, it also makes them heavy by the way they suck water in, when they get water logged they soon die and dead casters soon sour.
I'm well aware that some anglers will believe that my views on keeping casters in water are crazy.
If the cost of casters is an issue then why not turn your own, at least then you'll appreciate the effort it takes to get a quality bait.
In my view casters are by far a more superior bait than maggot, well worth the extra cost.