I would not buy a GSD (German Shepherd Dog) from an auction or website. You can browse the web to find a breeder. A reputable breeder will have had the hips checked (x-rayed) on both sire and dam. They will not have a hundred dogs and will need references from you.
There are websites for buying and selling lots of stuff. Craigslist does not allow animals, in general. I am expecting that there is some big website where all the people flock to where they advertise animals. That would make sense...competition in proximity makes for better competition. I'm looking for honest people in my area. I'm looking for a German Shepherd and Red Holstein in particular. ...I don't see what's odd about that. I grew up on a dairy farm; I know about animals. Where are they being advertised??? Is there like a Cletus List for farm animals?
Seriously prepare to construct your own reality, because you can be sure that right now somewhere in the world there is a group of people constructing one for you.
Try Ebay Classifieds. They sell everything from pets to livestock, and you can buy local. Be careful in the pet section. There are lots of rescues pretending to be breeders, and some of the breeders are not really "good" breeders. You have to be careful about the quality of the animals. http://www.ebayclassifieds.com/
Ask at the feed store. Find local breeders. Keep in mind that animals going to auction are culls, and just by being run through the pens and the ring at the auction sale, they've been exposed to more germs than a pathology lab.
IF you bring something home from auction, be sure to quarantine it and watch it carefully for a month or so.
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"No great thing is created suddenly." ~Epictitus
If you want a good German Shepherd, go to www.gsdca.org for a breeder referral. This is the official Parent Club for the AKC, their breeders agree to abide by a code of ethics and breed only health-tested dogs.
Now if you want a GSD that is cheap and you can get him tomorrow, by all means go to Hoobly.....but start saving for the vet bills that you'll acrrue when his hips/elbows go now
Can't tell you about the dogs, but we raise hogs, cattle and dairy goats. When I have stock for sale (or am looking) I list on CL (check the Farm and Garden section), Kijiji and freefarmclassifieds. The hogs that we raise are a rare heritage breed so I list them on the ALBC website. I dont know where you are in MO, but as someone else mentioned "the Big Nickel" as well as "star shopper" have online classifieds. As a rule I do not purchase from auctions.