How much is too much for a mixed breed dog.

So I want to start off by saying the closest dog rescue to us is a two and a half hour drive, and we have looked at them. We are looking for an 8-16 week old puppy and these rescues didn't have any. We came across an ad for a litter of pups near us, about 30mins drive. They are described as 7/8 shepherd and 1/8 lab. The woman is asking $350. Have been dewormed. No vet visits or vaccines. Pups are house trained and 14 weeks old. The woman is offering a health guarantee. If taken to the vet within 48 hours, and the vet deems an illness, you get the $350 back.
I'm just not sure. We like that they are a little older than 8 weeks and are housetrained and come with a health guarantee. But $350 seems like a lot for a mixed breed dog with no vet visits or vaccines. Thoughts...

Don't touch with a bargepole. Firstly, the description of the mix is very odd and rings bells. Secondly, they should have had their jabs by now. More important than the house training and I would be worried they had not been checked over by a vet at least once. Walk away is my advice.

House training might have started but don't expect it to be reliable until around 20 weeks and even then moving to a new home could disrupt it's training.
It should have started it's jabs by now.
As to your original question, I live in the UK where dogs are readily available but no I don't think it's overpriced for what may be 15 years of love, devotion and companionship.

Thanks. I thought it was expensive for an un-vetted dog as well. If the pup had received its first set of shots then I would be more than willing to pay. There are litters of dogs close to us, its jut about finding the right fit for us, which is seeming to take a while. We prefer mix breed rather than purebred too.

Wait, the right one will turn up eventually but you yourself has had alarm bells ringing in your mind. The right one will come. Take your time. Good Luck with your search.

Ok...so here is what she responded with, when I asked her about negotiating on price. Keep in mind I asked about negotiating because it is the ideal mix of breeds we are looking for, and the temperament matches our needs:

You need to look online on Ontario wide kijiji and be aware of the prices of puppies. It is not unusual but the norm to see the prices of several mixes of a pup to be $500 plus, with or without shots. These particular pups were listed and sold at $600 back at xmastime. The leftovers are going for $350 now. Also keep in mind that they are almost pure shepherd with just a little lab thrown in.
If you want vaccine and neutering for this price you need to go see rescues or the humane society but there is not much selection there, esp. at humsoc's. I think they're getting in the dogs and turning them over to rescues immediately so that they can say they had x amount of dogs in their care---except they cared for them a few scant hours. Producing these numbers, they get their funding this way from the city and Ont. govt....--though they claim they dont get it and rely on voluntary donations...but they do get funding. SPCA are well known for their lies that they tell the public.
The lowest I will go on these last 2 remaining pups is $300. My ad will be expiring any day now but I"ll be putting it up again til they're gone.

Either you want the dog or you don't, it's not something to be haggled over.
Not sure what on earth the second half of her reply is about tbh.

I suspect you are a total wind up Fluffy. GET BLOODY LOST. If you are not, then why the haggling? This is a difg not a lump of meat

I hear that £200 is a typical donation for a rescue dog in the UK. I'm not sure of the exchange rate, but I'm sure that rearing a 7/8 GSD to 14 weeks for $300 will not exactly make the breeder a fortune, and I would imagine that the reason that they are not vaccinated is probably that she has no money left to vaccinate them.
If what you really want is a GSD, which is vet checked, health tested and vaccinated, then contact the AKC for an approved breeder, and be prepared to pay the going price for that puppy. This is backyard bred puppy which comes - as all puppies do - with an element of risk. It is up to you whether want to take that risk, or take your cash elsewhere.

We specifically looked for a mixed breed. It's not that we weren't willing to spend the $300, as we were expecting to spend a little more actually. We were just concerned that $300 for a pup that has never seen a vet was a lot and we would be getting ripped off. We went and looked at the pups and we did take the brown male pup. He looks very healthy, is gentle, calm and social. Taking him to the vet on Tuesday.