Should i get a puppy or a rescue dog?

My friend's dog had puppies and is trying to get rid of them. they are part bichon frise and part rat terrier. he said he would give me one for free. but i am also thinking of getting a rescue dog instead because it would be a bit older and not as difficult to care for in the beginning with housebreaking it and everything. the problem is though that my relative come over a lot and one is allergic to dogs. since the puppy is part bichon frise he would have and easier time and the shelters ive looked at dont have many dogs that would shed much or have less dander than an average dog. any suggestions on what i should do is greatly appreciated.