Dover has expensive shipping but the worlds best return policy.
I love greenhawk it is good quality and good prices! :)
Depending on where you are there are some really good local tack stores with good equipment
I love equishop.com they have a LOT of good staff and they aren't that expensive as you would expect for example Veredus boots. I hope this helps :)
Stateline is usually decently priced and good for basics, Dover is generally overpriced, SmartPak is my favorite at the moment. Horze has some nice stuff. Schneider's too.