Well that is marginally better, although you are still encouraging the practise of breeding more dogs in a country where we are already over run with dogs and they are murdered by the hundreds every week for lack of good homes, for no reason other than money.
And you have to remember the strain that pregnancy has on dogs. Do you really want to hand over money to someone willing to risk their dog's life for some extra pocket money?
And then there is the risk that this 'one litter' breeder is lying and is either fronting for a puppy farmer (it is common) or is a frequent BYB.
A reputable breeder breeds only to improve the line of their breed, breeds infrequently and often only breeds when they need a puppy for working or showing. They will also source homes before they breed and have a waiting list, with stand by in case they are let down/end up with more puppies than they expect.
You should expect to be drilled by the breeder as though they were entrusting you with one of their own children and you should expect to have to sign a contract agreeing to return the puppy at anytime during it's life if you find yourself no longer able to keep it.
If you are not dead set on that particular breed there are loads of puppies in rescue, particularly at this time of year because people breed them for pressie money and then find they don't have enough buyers/enough money to raise the pups and dump them.
Scruples Whippet Rescue have whippet puppies atm. Whippets make excellent first dogs. Very easy going and laid back and don't need anywhere near the amount of training and stimulation a terrier needs. Impawtant Pups often has very young puppies.