It's great that you're thinking about having your rabbit(s) spayed. Spaying helps a LOT with litter box training, and of course also eliminates the risk of cancer of the reproductive organs. This kind of cancer is extremely common in female rabbits, so being spayed will likely increase the life span of any female rabbits you acquire.
Have you considered adopting rabbits from an animal shelter instead of buying them from a pet store or breeder? Some shelters have their rabbits spayed or neutered prior to adoption, which in many cases means that in effect you don't have to pay for the surgery. The Athens Area Humane Society, for example, adopts out rabbits who are spayed or neutered for only $30, and as a bonus even throws in a copy of the House Rabbit Handbook. I know it's a long drive to Athens, but $30 is an extraordinarily low price.
To avoid making the drive to Athens only to return empty-handed, I recommend going to the Humane Society's web site at http://www.athenshumanesociety.com/ , reading about the adoption procedures, and printing the "small animal adoption profile" form and filling it in. Then, call the Humane Society and see if they'll let you fax or mail the form to them so you can be pre-approved before making the trip. It would also be a good idea to confirm by phone the hours they're open and whether you'll be allowed to bring your rabbit(s) home with you that day.
If you don't immediately see rabbits on the Humane Society's web site that you'd like to adopt, check back often over the next few weeks because shelters are likely to receive a LOT of rabbits over the next few weeks and months as a result of the Easter holiday today. Too many people celebrate Easter by giving cute little rabbits to their kids, and many of these rabbits are abandoned shortly after Easter when the kids who were given the rabbits become tired of them and the kids' parents realize they don't have the time or resources to care for a rabbit for 8-12 years. Shelters become full of these discarded "Easter rabbits", and you could save a life by adopting one of them.
By the way, although low cost spay/neuter clinics for rabbits are available in a number of communities, other types of veterinary care are seldom offered at a discount, so it might be a good idea to start saving now in case your rabbits need to go to the vet at some point in the future to be treated for injury or illness. Be aware that not all veterinarians know how to treat rabbits, so you may need to hunt around to find one with expertise in treating rabbits. The House Rabbit Society has an article at http://www.rabbit.org/faq/sections/vet.h... with suggestions on how to do this.