Welcome to BW!! there is so much info here, you will find answers to all your questions.
Re: price. it really depends. here in MD you can get a boxer pup for 300-400 but from a BYB (the pups are AKC registered but the health testing wasnt done, this is different then a vet stating the dog is healthy, and not up to standards) petstores charge 600-800 (same as byb's but in more volume) and "responsible, ethical"breeders are 1000 - on up, these are the breeders that make sure the parents meet the standards and do the appropriate health testing
What is your little ones name? can not wait to hear stories and believe me you will have stories. you will laugh, cry, and get fustrated with your boxer but in the end being owned by a boxer makes it all worth it, life is never dull :D
again congrats and WELCOME!