Price should not be the determining factor in getting a dog that you are going to hopefully spend the next 8+ years living with.
You also will likely never, ever find a well bred Doberman for any less than $1000. And even that is kind of on the low end nowadays it seems.
I'd recommend heading to the DPCA website to their breeder referral
page and start there. You might pay more upfront for a well bred dog, but with all of the health testing and certifying (hips, thyroid, elbows, cardiac, etc.) and titling (and thus proving temperaments) good breeders do with their dogs, you stand a much better chance at getting a healthy dog and paying less in vet bills over the course of the dog's life.
And yes, dilute Dobermans (fawns and blues) tend to have more skin and coat problems than their red and black counterparts. It can happen with all colours (I have a black and a red with follicular dysplasia), but it's much less common with reds and blacks. And I'd say that most poorly bred dilutes will very likely end up with pretty severe hairloss. Some backyard breeders like to sell their dilute puppies for more money because they market them as 'rare', but they're not actually rare and should not cost more than black or red puppies.
And keep in mind that just because a puppy is registered, that doesn't mean the dog is well bred. Especially if you're in the US and getting a US bred puppy with a 'CKC' registration... I can pretty well guarantee that that is not a Canadian Kennel Club registered dog, and rather a 'Continental' Kennel Club registered dog which is not a respected organization as far as I've ever heard. But regardless, even backyard breeders can register with AKC, so having a registered puppy does not mean you're getting a well bred puppy.
A good breeder is one who will interview you, ask a lot of questions, have a contract to sign, doesn't breed very often (I like to see two times a year max, maybe three, depending), puts a lot of thought into their breedings, knows the litter's pedigree inside and out, will probably pick out your puppy for you (because they have a better idea which temperament will be best suited to you after living with the litter for 8-10 weeks), has ears cropped before leaving for new homes, screens for health issues as mentioned above, titles their dogs in different venues (conformation, Obedience, Agility, protection), and will always take the puppy back should you no longer be able to care for it. There are a lot of other things that constitute a good breeder as well.
If you do not want to pay upwards of $1000 for a dog, I recommend going the rescue route and adopting an adult Doberman or even a puppy (often rescues have puppies). The more people there are that support bad breeders, the more bad breeders there will continue to be. And that's not good for anyone. Not the owners who are ending up with dogs of unstable temperaments or health issues, not the dogs involved, nobody.
Good luck finding the right puppy for you! It's definitely worth the time and effort to seek out a good breeder or go the rescue route.
ETA: Apparently I took too long to type all this and others responded already! But I echo the idea of it probably not being the best idea to bring in a Doberman puppy with two young children. Doberman puppies are hard work. By far my Doberman puppies were the most difficult, high energy, all over the place, unfocused puppies I've ever raised and my family and I have a lot of dog experience with a lot of different breeds. Our first Doberman was adopted through rescue, as a 7 year old adult, and he was an awesome introduction to the breed. He'd have been the perfect family dog for someone with small children. Very trustworthy, patient, tolerant, and was active but not active like a puppy would be. A dog like him, through a responsible rescue organization, would IMO be a much better choice than a BYB puppy or any puppy really at this point in time.