$1000-$1500 is the current market for a well bred GSD. It's not about you showing, or breeding, but the titles in the pedigree tell you that the parents/grandparents/so on have been tested to have solid temperament so that means your boy/girl is likely to have good temperament.
I'd start contacting breeders, but unfortunately, many are probably not going to be to happy to admit they've produced livers. A good breeder is likely to not repeat a breeding that produced a liver as it takes two recessive genes and so the way to avoid that (knowing that both parents are carriers) is to not put them together again.
Personally, I wouldn't expect to pay "full price" for a liver. I'd expect the breeder to discount that dog because even though you're not interested in showing now, if you ever do get interested, the fact that the dog is a liver disqualifies you from showing. So although working/obedience wise your dog could be just as successful as any, you are automatically eliminating a venue from your list of possible things you can do.