Where do you buy postcards in the USA?

Hello, Postcrossing community! Where do you buy postcards in the USA? I was looking on Amazon, but I suspect many people purchase them there. I don’t want my postcards to end up in the trash because they’re similar to others sent from the USA. In local stores, most postcards tend to be outdated or unattractive. I plan to create my postcards soon by printing my professional landscape photos.