As Sue indicated, this is really a much more complicated question than it appears on the surface. And also is going to vary WIDELY from dog to dog, breeder to breeder and situation to situation.
In our case, we have a dedicated room at the side of our house, right off the living room, for whelping and puppies. It is an indoor/outdoor set up with a doggy door through the exterior wall of the room to a 10x10 outdoor kennel on a raised brick patio. Cost for all that, converting a former screen porch into a room and building patio and erecting kennel was around $5000. We did all the work ourselves. If we’d hired it done it would have cost probably twice that. But while very nice to have, such a set up isn’t really needed.
Our whelping box was made by my husband out of PVC privacy fencing. About $300 in materials and hours of labor to construct it. For box, flooring and exercise pen to finish off the indoor enclosure, probably total cost around $500 and again that doesn’t include labor. A homemade wood box would have been cheaper but still for box, flooring and e-pen at least $200 or so.
Then there are all the supplies that must be on hand. Bulb syringes, thermometer, hemostats, surgical scissors, heating pads, heat lamps, dental floss, quick stop, oxytocin, syringes and needles, suture and needles, puppy ID collars, puppy feeding pans, gram scale, baby scale, laundry baskets, towels and blankets by the truckload (and laundry soap to wash them), cleaner and disinfectant. At least $200 in general whelping supplies, though of course most are reusable from litter to litter.
Not counting the dedicated room and kennel, just the whelping box and enclosure and supplies we’re at about $700 for initial investment for supplies. All stuff you need whether you’re having one litter or ten litters.
The next biggest variable is the bitch. This will vary widely as well. Does one get an adult, proven broodbitch to start with? A green dog to raise and train and title and eventually breed? Or start completely from scratch with a puppy?
We tried the adult, titled, proven broodbitch route once. $5000 for a dog, plus $900 shipping. Between stud fees, shipping to and from stud for natural breedings and also trying AI breedings (paying for semen collection, shipping, and transcervical insemination by a reproductive specialist) we racked up another $5000 or so trying to breed her 3 times. And we never got any puppies out of her. So over $10k invested for no pups at all. She ended up being spayed and becoming the couch queen. She was a fantastic dog and wonderful companion, but that’s a pretty darned expensive house pet!
We tried the adolescent green dog route twice. Both were purchased at 15 months old for $1800. Thousands more invested in the next few years raising, training, titling and health checks. One worked out and ended up becoming our foundation bitch. The other had reproductive problems and was unable to conceive a litter. $3000 or so invested in trying to breed her and then in testing to find out why she didn’t get pregnant, before she was spayed and placed with a family. So for the one, all that money and time invested paid off in puppies. For the other, thousands of dollars, years of time and lots of heartbreak over not being able to get puppies.
Then there’s going the puppy route. Cheaper initial investment, but much greater risk as to whether the puppy will develop into a good breeding candidate. Will it pass health checks? Get titled? Will adult temperament and structure and everything else be suitable for breeding? And then if yes to all that, will it be able to reproduce or will it have reproductive problems. I prefer the puppy route myself, but also accept that choosing this route means that realistically I’m going to end up washing out 2 or 3 pups for one reason or another for every 1 that turns out to be a good breeding candidate. Including one we raised and got through the whole health testing and titling process and then decided not to breed. So thousands more dollars invested in those wash outs, plus months or years of time, and again a lot of emotion and disappointment when they don’t make it. And that’s starting with well bred pups from known bloodlines who were carefully selected as possible breeding candidates from the beginning.
Many other costs can’t even be quantified. Hours spent researching pedigrees and bloodlines, not just on the internet but many hours of long distance and international phone calls as well, and the phone bills that go along with that. Trips to training and seminars and trials to see dogs in person and talk with people in person, and the gas, hotel, and other travel expenses associated with that. Bloodline research software for the computer. Kennel/breeding management software for the computer. Quarterly genetics CDs from the SV in Germany. Membership dues and training fees in various GSD and training clubs and organizations. All stuff a breeder should do IMO, but the costs of which can’t be broken down on a litter by litter basis.
And then there's the question of just general upkeep. I wouldn't consider normal feeding and vetting and all the paraphernalia that goes along with dog ownership as a true breeding cost, because we'd have dogs whether we bred them or not, so those costs are always going to be there. And in terms of general maintenance we don't do anything differently with the breeding dogs than with the non-breeding dogs. Same for training costs. We'd train and title whether we bred or not. So I don't see those really being direct breeding costs eater. What would be different is that we'd probably have fewer dogs in general to care for and train if we didn't breed. So in that sense breeding does raise the cost because it means more dogs, and doing all those things with the dogs who are retired from breeding or who were never breeding dogs in the first place, and the young dogs that will hopefully be breeding dogs in the future, as well as the actual breeding dogs themselves.