I don't have pigs now , but DD and I shared eight over 8 years. ( Had five at one point in a group of 2+3 )
Pricewise-
Vets are expensive, we went to a guinea- pig specialist. Not much more expensive than a regular vet, an hour to drive there but worth it for the expertise.
Our boar was £60 to castrate
One piggies was £30 to euthanise
I did claw clipping and bought shampoo and Xeno 450 online
Hay was the next expense , they went through bags of it, I didn't ever but baled equine hay as it can have sticks in it ( I used to ride horses so I knew from feeding them). I did but equine readigrass which was fine .I bought the big packs from the Range ( usually 2 a week) and Jolleys which was nicer for eating .
Housing, outdoor runs , . We had a wooden play house to hat DH modified. Small heater , fan, those microwaveable rubber discs that you heat and stuff into their bedding .
I used puppy pads and IKEA fleeces ( they wicked well as they're not fluffy , cost about £2 each)
Holiday boarding was around £10/pig/ night but discount for shared cages
I didn't buy insurance , some of mine never needed a vet , others did. I looked at prices when we got the first two but it was difficult to find a company, cats dogs and rabbits mainly
Vegetables you can grow your own, buy from a market , sometimes pick up a bargain in reduced. Only caveat is "would I eat this myself?" If it wasn't safe for me it wasn't safe for my piggies.My shopping trolley looked SO good but I realise how invested I was muttering "Oh they don't like lambs lettuce, oh good leafy sweetcorn or leafy carrots" because they are fussy 😄
The cost of the piggies was on average £10 but we paid more for a tiny piglet and for a ready castrated boar ( because I knew the cost having got one of our boys done)