Hi Alexandra, Dover Saddlery has some nice pads and an online store. If you are willing to spend the money I highly recommend Ogilvy pads. Both the half and regular saddle pads are great. They come in a ton of fun colors, so you can have fun customizing them to your barn or favorite colors!
You could try Dover Saddlery
A good idea is to go to the wed site My stable and they can probably do it for you.