You can't just buy an owl as a pet.
All native species of birds in the USA are protected under the rules of The Migratory Bird Treaty Act.
Owls don't make good pets and keeping one for any reason, other than rehabilitation, would be cruel as well as illegal. If the fact that it is illegal doesn't deter you from wanting to own an owl, here's some disgusting facts. You have to provide live food for them...what they don't eat, you need to remove...so prepare yourself for picking up parts and pieces of rodents or whatever the small animal de jour is. Owl poo is very loose & nasty. They also barf up parts of what they eat.
If you still think you need an owl, you need to check into what steps you need to take to become a licensed falconer. It's not an overnight thing..takes time, effort and money.