Another good possibility is sheltie rescues. These are shelties that for some reason or another, were not able to stay with their owner and need a new home. People want to breed dogs for a lot of reasons. There are lots of other people already breeding dogs that are every bit as special as yours. Seriously, there are better ways of experiencing Nature at work than bringing more dogs into the world.
Breeding is a dirty, messy, job at times, especially as the puppies get older.
Temperament problems are often the result. Next, we have the money-desiring people. Any reputable breeder will tell you that you cannot make money breeding dogs if you are doing it right. Skimp on the vet care of the mother and puppies, feed low-quality food, skip the genetic screening, save on stud fees by breeding to some local male of low quality, and maybe then you will make a little money. This is assuming the puppies don't have to be put down for some disease or health problem.