Before going ahead and looking at a litter there are so many things to consider.
Have you really looked in to the background of the breed? How big will it grow? Have you got the money for vet treatments for injections and if the puppy becomes ill.
What will you do when you go on holiday, how long will the puppy be home along.
Do you have the time and devotion to train the puppy? Will breed of puppy will best suit me? The breed of the puppy will depend on your preferences.
Your lifestyle do you want something that can be let out in to a large garden and run around or are you a keen walker and want a dog to accompany you on trips to the sea side and walking in the lakes?.
Read up on the breeds of dogs, consider there exercise requirements and their temperament if you have children and other pets.
A dog should be chosen on its ability to fit in to your lifestyle.
There is no point buying a working breed such as a highly energetic Springer spaniel, taking it out twice a day for the first few weeks then giving up.
Dogs and puppies that are bored and under stimulated may become behaviour pests that constantly bark and chew to create a distraction from being bored.
Cost of food, is always a point that is missed when you do not think everything though.
The bigger the breed the more food they need.