Their diet is unlimited hay first and foremost.
They can then have one cup of veggies per pig per day.
Then it’s just one tablespoon of pellets per pig per day.
(Being in the uk, my prices are in pounds)
Cost if hay is going to vary depending on what you buy. Some people only buy and store smaller bags (which can work out more expensive).
It doesn’t have to be Timothy hay, any grass hay is fine.
I buy hay in bulk but I have five animals . I buy bales of meadow hay from a local farm and a bale lasts around six weeks. That costs £7.
I also buy a smaller bale of orchard hay online which lasts five weeks and costs £30.
Veggies are just part and parcel is what I buy with our own veg and salad. I estimate it to be around £10 a week for their part.
Pellets - well I hardly feed any (they only get pellets 2-3 times a week and even then it is less than the recommended amounts) so a 1.5-2kg bag of pellets lasts me around six months. For others who do use pellets daily then a bag will last a couple of months.
The biggest expense is going to be vet fees. It’s best to save up a vet fund so you can get them help promptly whenever an issue arises. I like to have between £500-1000 per animal put aside for any emergency.
Long Term Balanced General And Special Needs Guinea Pig Diets