Hi Nicky,
That's a bit of a "how long is a piece of string" type question. Where in the world are you? What sort of budget? Have you anyone to go shopping with you? Are you happy to shop alone? Are you willing to shop online?
You don't need to answer these, just consider them.
Thrift(charity in the UK?) shops in well-off areas will often have the types of high quality clothing you describe for very reasonable money. I have bought many expensive items of clothing for knock down prices from ebay, though I know many people dislike ebay. You need some idea of your sizing to shop online and that varies from brand to brand. I started with very cheap items and a guesstimated size until I was sure of my sizes. Most of what I buy online now fits perfectly.
I go shopping with my wife but usually only for cheaper clothing. The high street is way too expensive for me in posh shops. Hence online where real bargains are to be had.
A word of caution. Online clothes (and shoe) shopping can get addictive. I have way more dresses than my wife and need a whole spare room to store them in.
Very best of luck and best wishes to you.
BP