There are ways you can cut costs if your current spending is becoming a bit of a burden. I have always raised my rabbits on dry feeds (pellets and hay) only. Not all of my rabbits are pets, I do breed and show some. However, their "purpose" doesn't drive my diet of choice. Our rabbits have always been healthy and have required little veterinary assistance over the years (3 visits total - we've had rabbits about 13 years).
If you would decide to modify their diet, companies like Manna Pro, Blue Seal, and Purina do have formulas specifically for pet rabbits. They're usually sold in 25 lb. bags, I think, and are around $8-10. This would feed 4 rabbits for at least a month...most likely two months, but I'm not sure what size rabbits you have.
With hay factored in as you described above, feed may total $20 or under per month. So that could potentially be a huge cost savings. We do grow some fresh herbs and vegetables to supplement as treats in the summer, but do not feed fresh vegetables on a regular basis.
You can also save on veterinary bills by becoming knowledgeable about different rabbit ailments and how to treat them. Since rabbits don't require vaccinations or regular vet care in the U.S., most things can be successfully treated at home. In fact, there is so little research about domestic rabbits (in comparison to dogs, cats, etc.) that you can quickly become more familiar with the things that may ail your rabbits and how to treat them than many veterinarians. Knowing when and how to treat common illnesses can save hundreds of dollars in medical bills annually.
