I'm just so not into the puppy back business. Many people get scammed that way. I know of breeders who do this pyramid puppy thing where they sell a bitch pup on a puppy back agreement, take back one or more bitch puppies, and sell those on a puppy back agreement, etc. They can make good money doing that, but in my opinion, it's not ethical.
I also know a person who got a bitch from a certain breeder, paying full price. Showed the bitch to her championship, and after consulting other people in the breed, decided she really wasn't worth breeding. To get out of her puppy back agreement, she had to pay for the bitch again.
My own introduction to breeding was with a bitch that I did not get with intention of breeding. I got her for pet/sport, and decided to try showing, since the breeder said I could. Tully didn't do well in shows, but I eventually decided she had strong virtues that the breed could use, and considered breeding her. She was co-owned, since the breeder doesn't let intact dogs out on full ownership. I contacted her, she didn't have a problem with Tully being bred, and suggested a couple stud dogs for me to choose from. I was glad of the help.
I picked the best one, who was available through frozen semen, and did a surgical AI. Tully conceived, and the X-ray showed 6 puppies. The next day (a few days early), she went into labor and delivered 4 very small puppies, then stopped contracting. I called the emergency vet (weekend), and the person who answered the phone told me not to worry. I worried. After a couple more hours, I called the emergency number at the vet where the AI was done, and the vet there was very concerned. He told me he'd meet me at the clinic.
4 tiny puppies in a box, a still-pregnant bitch, and me loaded up in my 2wd pickup and drove 25 miles on ice to the vet hospital. The vet tried for awhile to induce labor, finally calling another vet to come in and help with a C-section. At which point she finally popped out one very dead puppy with a leg pinned back (the holdup), and another dead pup that had been stuck behind it.
At which point the vets got worried about the 4 tiny puppies in a box, which weren't doing as well as they thought they should, and started working on them. They finally sent me home with equipment and instructions for tube feeding. I went home, and over the next 36 hours, watched 3 tiny puppies die. The first to die was the biggest, strongest seeming puppy. Finally I was down to one. Who turned into the fattest puppy in the universe, and eventually became my Tess. After 4 weeks or so, I finally stopped thinking she'd drop dead at any moment, and named her.
There's no way I'd force someone else to go through that. If somebody wants to breed, and is aware of the hazards, okay, but I would never, ever tell someone they had to risk their beloved pet because I wanted a puppy out of her. My Tully could easily have died in her horrible whelping, if I'd followed the advice at the e-vet, or under anesthesia during the C-section if she'd waited 5 more minutes before popping out those 2 dead puppies.
I didn't pay for Tully, btw, she was given to me by the breeder. Who also offered to give me another puppy, if I didn't want to breed Tully. She wouldn't have required me to breed that one, either.
Now, in Tess' litter, I did have trouble choosing between my 2 live pups (I lost one at birth). I eventually picked Pirate, but I did really like his litter sister. Still do. Would have loved to have pups from her, but the person I placed her with doesn't want to breed, and there's no way I'd force it. I could have looked for a home that would be willing to breed, but I wasn't going to keep her from the best home in the world because I want pretty stripey puppies.