The Polish Lowland Sheepdog is of medium size with females standing 17-19" at the top of the shoulder blades and males standing 18-20". Average weight is approximately 30-55 lbs. Although the dog is typically kept in long coat for showing purposes, it is considered to be virtually non-shedding, and a possible choice for people with allergies.
If you have decided that this may be the breed for you, it is essential that you invest the time and effort to find out the advantages and disadvantages of owning this sheepdog. Most areas have AKC dog shows where PONs may be competing in conformation, agility, obedience, or rally depending on what the host club offers at that particular show. This can be a great avenue to meet a PON and talk to its owner to see if this is the kind of breed you would enjoy. A search on the AKC website will take you to the "Parent Club" of the breed and will have contact information for someone who can speak to you about them. (A Parent Club is the governing body recognized by the AKC and the Parent Club's purpose and primary goal is to educate the public on the breed, support the breed in the US, and promote and protect the breed.)

(please see "11 Things To
Know BEFORE Purchasing a PON") 
Talk to exhibitors and breeders. Try to visit at least one kennel. Be honest with the breeders you visit with - either in person or by phone. Tell them what you are looking for in a PON and whether you want a companion dog or show dog. As a novice, the more information you know, the more informed about the PON and it's requirements you will be. Don't be offended if the breeder asks YOU many questions as well. An ethical and responsible breeder cares about the welfare of his puppies and wants to be sure each one is placed in a home that he is suited for.
Purchasing a PON is a considerable investment. Be prepared to spend between $1800-$2500 for a QUALITY puppy of this particular breed. This is primarily due to the increasing popularity of the breed and the limited, but increasing, number of breeders of the PON. Considering the lifespan of the typical polish lowland sheepdog is around 10-13 years of age, around $180 a year is a small price to pay for such a devoted family member!  
Fortunately, the breed is a relatively healthy one. If you purchase your puppy from a responsible breeder who has tested his breeding stock for the few known inheritable health problems of hip dysplasia, PRA (eyes), and hypothyroidism, you will increase the odds of your puppy being a healthy one. Ask to see copies of the dogs OFA certificate (the dog should be rated as having hips that have passed with a fair or better grade) and CERF (the dog will be given a number if it has passed it's eye exam or ask to see copies of the dogs exam- this should have been done within a year of the dog being bred) While thyroid testing of dogs is not always routinely done unless a dog shows symptoms of the disease, it is still a prudent idea to have it done on your breeding stock. Please keep in mind that a PRELIMINARY OFA test result (done at six months of age until under two years of age) does not necessarily mean the dog will pass its OFA when it reaches two years of age. Two years of age is the minimum time OFA has determined to be the earliest at which they can give an accurate hip rating. PENN HIP is another relatively new test for hip dysplasia that breeders have at their disposal. This method gives a distraction index (DI) based on the degree of hip laxity at the age of approximately 4-6 months (at the earliest). (A rating of 0.3 means you can "virtually guarantee" the dog will not develop hip dysplasia - 0 being the best and 1.0 being the worst rating). A rating of more than 0.3 is a somewhat fuzzier issue. The relationship between DI and degenerative joint disease is breed specific. Therefore there must be a sufficient number of dogs in the database to determine whether a DI of, say, .48 means a dog would most likely develop sound hips or bad hips. For some breeds a .48 would indicate good hips but in others breeds it would indicate loose hips. If a breeder uses the PENN HIP method it would be most advisable to ask for proof that the puppy is from parents with at least a 0.5 rating until such time as there are adequate numbers in the database to determine if that number might be adjusted.
Another point to consider is whether the puppies have been exposed to children and adults in the household when growing up AND preferably many other children and adults they don't see on a regular basis. Socialization is a very important factor in the temperament of the growing dog from the time of birth.
Many good breeders will also begin the "potty training" process with their puppies to make them easier to housebreak for their new owners. Depending on the climate and time of year the puppies are born, it is helpful if the breeder takes the puppies out of the whelping box on occasion and/or takes them outside so they do not become accustomed to eliminating only in the area in which they live. If puppies are only allowed to eliminate in their whelping box/puppy pen, it takes away their natural instinct to keep their den clean and makes it very difficult for the new owner to break this habit. Typically a PON can be potty trained very quickly if they are given a good start as pups.
Is the Breeder home during the day with the puppies to spend time with them and care for their needs throughout the day? A breeder who has another full-time job has very little time to spend socializing, caring for a puppy that may have gotten off to a slow start, keeping their puppy pen clean throughout the day, and beginning their training (leash training, potty training, etc.).