In my case, getting a second caused more vet bills. Otto has never been sick, but Hannah has had her teeth clipped and has needed to visit the vet more often. That can happen with any rabbit, but it is a lot more money even to take them for a standard exam (where I live that’s $90 per rabbit – quite an increase to pay double!) I don’t use insurance because I find it cheaper to just have some money put aside.
The veggies are much more expensive. I now spend at least $10 a week on veggies for two, up to $15 depending on where I shop.
I don’t find that hay and pellets really cost me more since I buy hay in bulk and they hardly eat any pellets.
Their living space is the same size that Otto’s was as a single bunny – 4’x8′ – so that wasn’t a change, though having to rearrange everything while they were separate was hard.
Basically it’s what you would expect – vet care and food does cost twice as much and you might want to make a bigger habitat. At first having a second was hard – bonding was fairly easy, but they still got into tiffs after a month of living together so I was a bit stressed about their situation for months. Now I love having two. Otto doesn’t really seem happier, though he likes having a friend. I think Hannah really needed a friend and she is so much more relaxed.