I’m so sorry to hear about this experience. The holidays are not a good time to get any new pet because of all the activity and extra people who are around. Kids are busy with new things, adults are distracted and a new bird can be very stressed and not eat as a result. The new parakeet may have been sick or simply didn’t eat due to stress and sadly died.
When things are back to normal after the holidays, this is a better time to look for a new pet. Pet stores can have good, healthy birds as well as breeders can, Just like anything, there can be good and bad pet stores or breeders. A young bird is best and ideally you want one that can be handled before you buy it. Some places will sell you a young bird and tell you it will tame down. Some will, some will not. To avoid another negative experience, try to find a store or breeder that has parakeets that are already tame.
Here are some links with articles that will help you get started:
Caring For Your Bird
Happy new year!