As a general rule, the breeds you mention are bred for money with little or no concern for the genetic health of the puppies. This means that while you may find what you think is the perfect puppy - you may find that as it gets older it has hip dysplasia, which can be crippling and expense to repair and other crippling or deadly genetic issues.

There are several AKC recognized breeds that are recommended for allergy sufferers and many ethical breeders that are just as concerned with the puppies genetic well-being as they are the "look" of the dog. Poodles come in three different sizes and are very smart dogs, considered easy to train and generally wonderful with children. Yorkshire terriers, Bichons, and Portugese Water Dogs are also great dogs that are usually good for allergy sufferers.

I think that you will find that a puppy of one of these breeds from an ETHICAL breeder will be comparable in price to a "designer" mix.