English saddle shopping can be a nightmare. We can all give you what fits us but it's like finding a pair of jeans that fit you. A real PITA. And yup, go used rather than new and cheap. They are cheap for a reason. Unfortunately you get what you pay for and it seriously makes a difference in your riding.
I would look for used:
Courbette, Collegiate, Wintec (I don't like them either), Crosby, Stubben.
Steer clear of non-name brands and I don't like Crumps.
When you have a saddle on trial, take it to your instructor so he/she can assess if it fits.

Average, for horses with some experience at this level