I guess I would say it depends on your reason for breeding. Hobby breeders, like myself, usually are just breeding for pleasure, not profit, and tend to breed animals that are sold as pets. We strive to breed the highest quality we can, but ultimately this is not our livelihood, and the main goal is to produce healthy, "nice" chinchillas who will be good companions to their owners.
The chins on that website, which I believe is owned mainly by Ritterspach, are mainly aimed at professional breeders and furriers. Those people make their living off the quality and saleability of their animals. By the way, $500 is a way low price from what I have seen on that site. I have seen them routinely auction off animals for more than $1000. I would bet the price on that girl will go up before too long...there's still two days left on her bidding time.
So if you are not breeding for profit then, to my way of thinking, it doesn't make sense to sink that much money into one animal. But, if you are looking at breeding professionally, buying those chins might be a wise long-term investment.
I would also suggest, if you have fellow breeders nearby, you could always buy (the males, at least) jointly, which cuts the cost for each person significantly, and then share him as a stud male for your individual females. I have heard of breeders using that strategy to make it more feasible to purchase very high quality show animals.
Also, you should also notice that the animals auctioned off are show animals. But you can also purchase chins from Ritterspach that are perfectly good for breeding but lack one of the characteristics they look for in shows. Those animals are much more reasonably priced if you are willing to take the time to find a mate who compliments them well, to produce better kits.
