I like horse.com's website the best for navigation and narrowing down items. Advice: Create an account and add items to your shopping cart. Then close the website and walk away.
Within 3 days you will start receiving emails with discounts off your shopping cart and free shipping.
I've heard that horse.com does that! Never knew if it was true though, thanks for the input.
Back to topic -- I've gotten my pads from Dover Saddlery and have been happy with them so far. As others have said, you get what you pay for. Better to go bigger in the $$ because it will take you a whole lot farther down the road. Scout out the sales and closeouts, and take advantage of free shipping when your purchase qualifies!