I wish I had a trio. I did consider adopting a duo to pair with my bunny but I did find that they were more expensive.
Here is how we broke it down (per bunny):
insurance: £13 a month
health plan: £11 a month
hay: £30 for six months / £5 a month
pellets: £18 every three months / £6 per month (I feed two brands of pellets)
litter: £19 for three months / £6ish per month
toys: £30 every few months / £10 a month (this varies)
grooming: £12 a month
total: £63 a month per bunny
Now, of course, the bunnies would share most of these things, but they’d last less time so that would need to be factored in. The main thing for me was the insurance, health care plan and grooming (so I suppose the maintenance), for one bun it’s £36 a month, so with three it’d be £108 and for four it’d be £144. Wowie
but if money isn’t a problem, having a trio or a quad, seems pretty similar to having a duo to me. They run around together, they sleep together, they eat together, and they’re pretty small, so it doesn’t tend to feel like a big difference (especially if free-roamed). If all the bunnies are litter trained and hay is kept in one main area, cleaning should also be quite manageable. Just hoover or sweep every few days to keep it tidy.
I don’t have a trio (or even a duo, though my bun had a girlfriend in the past) but this is just what I think. hopefully it helps