A purebred puppy will be expensive. Depending on the scarcity and popularity, expect to pay anywhere from $250 to $1,500.
My Strongest Recommendation - Attend a few dog shows so you can:
You see what small dogs in that breed should really look like (a problem for over bred and poorly bred dogs such as Pomeranians and Toy Poodles);
You can buy a program that will have names and addresses of breeders, owners, handlers and other dog business people This can be a valuable resource when you need a referral; and
You'll see what Toy breeds are capable of doing, and you may be amazed.
How do you find a dog show? Easy! Check the monthly magazines, dog Fancy and dog World.
Other Things to Consider
All Toy breeds make good companions for adults, but given their small stature and weight, they are not the ideal family dogs when small children are present. Many are fragile and cannot withstand rough handling.
Whichever breed you select, please do not get any dog advertised as being a "teacup." Toy breeds are small enough as it is, and a "teacup" almost guarantees you will wind up with a sickly and high strung dog.
Be sure to ask the breeder or seller whether the parents had X-rays and veterinarian clearance.
Organizations that provide official clearances are the Orthopedic Foundation of America (OFA) for hip disorders and the Canine Eye Registration Foundation (CERF) (Link) for cataracts and progressive retinal atrophy (which always leads to blindness).
To reduce the risk of genetic problems, you should take your new pet to a veterinarian as soon as possible - before the bonding process is complete.
Genetic problems may require expensive surgery, and you may have to decide whether to return or keep your pet.