To my knowledge NPIP testing for certification is free in the state of Texas. It is a test specificallly for two diseases for all states. Then there are other tests that some states do in addition. If you want to show you have to have the certification.
NPIP is a certification that says that the breeder's flock is free from two diseases that can be passed from hen into egg and thus chick. The American Poultry Association APA is planning to restart their flock certifications, and probably already has certified a few flocks by now. This certification is in regards to the Standard of Perfection SOP.
It is still a good idea to ask about their breeding and husbandry practices if you are purchasing from a small breeder versus a hatchery.
NPIP is not free. The basic pullorum/typhoid testing that is done in TX is not the same as having an NPIP number. NPIP has more paperwork and regulations for the breeder to follow, such as not obtaining stock from non-NPIP entities and keeping paperwork on who buys your birds in order to track birds, and more frequent testing. Earlier this year the cost was around $100 for registering for an NPIP number, but may have increased since there were changes that were going to be looked at when the new registration year began in July. That cost did not include the laboratory testing fees for avian influenza. Before the new registration year started this summer, TX NPIP was pullorum/typhoid mandatory, but you could also add the optional avian flu testing. Not all states have optional testing and make everything mandatory that they feel is important.
Each state determines what testing will be done for their version of NPIP, despite the idea people have that the requirements are the same across the country because this is named the *National Poultry Improvement Plan*. Some states only worry about pullorum/typhoid, others require testing for additional diseases. This is why many good breeders do not worry about NPIP testing because they are not raising birds to make lots of money. So the requirements and cost of getting an NPIP number is not worth it, because the individual states have different requirements for NPIP and what is ok for NPIP in one state may not be enough for another state and the person would have to get additional testing done on their birds if they were to ship birds to a state with a more rigorous testing requirement.
Yes, the APA has certified a couple of poultry flocks as being uniformly consistent with the breed standards for the breeds of poultry they keep. From the discontent I've seen posted among APA breeders, sounds like it may not be as popular as some people thought, due to concerns over how this flock certification came about and the requirements for it.