hey
First off, Please do some research into the breed before you buy one. You want to look into finding an experienced, knowledgable breeder from which to buy your dobes. Dobermans are a breed that are plagued with health problems and lovers of the breed ( and the majority of people on this board) are trying their hardest to improve the breed by supporting responsible breeding ONLY ( ie, no pet stores, no backyard breeders, no internet...) As for average cost, that is hard to say but for a quality pup expect to be spending quite a bit. Please remember that you will probably pay the same amount for a pup from a responsible breeder as you will for a pup from a backyard breeder and you will get a much healthier happier puppy!
As for finding one before christmas, that is a rather unrealistic goal since most good breeders have waiting lists on pups or atleast require more than 4 weeks notice.
For what a pup should come with, there is a HUGE list. They should come with their first set of shots, a pedigree and should be registered ( CKC, KC, AKC depending on where you are from) unless you are willing to rescue! Which is an awesome alternative. You should be able to meet the parents, look at the grandparents and see proof of health testing from all of the above ( tests for vwd, involved in a cardio program, hips, eyes, elbows certified etc).
I did my best but I'm SURE that the experts will fill you in! Goodluck! Dobes are the best.