Speaking of cost....
That said, I have to wear professional attire 50% of the time (a uniform
the other 50%) and I buy 100% of my clothes from the Goodwill store or local consignment shop. You don't need to spend a lot of money. I buy entire suits for under $10 (nice, modern, very lightly used) and all pants/shirts for $3.38 I like the brand Talbots for my dressy-clothes (classic colors, classic lines, high quality, less trendy) but not Talbot prices LOL. I can usually get 5 pieces for under $20. You can't go wrong with dark pants, tailored white shirt and maybe a jacket if it's cool outside. Simple jewelry, and minimum perfume. I should add that everything I buy is pretty conservative, but I like modern styles and neutral colors to improve the mix-and-match issue. Too trendy means you have to update more often.
If I have more $ to spend, I go to a ritzy consignment shop here- you can get expensive shoes ($150+) for about $20. I have 2 good pair of shoes- that are stylish and high quality. I wear them with everything business. You have to know me- I don't often spend $20 on anything LOL, so that's a splurge, the rest of my shoes come from Walmart! If you plan to shop the thrift shops, give yourself a few weeks. Don't buy crap- just leave and come back another day. They put new stuff out every day, so after a week or two you will have found what you want (I'm certain of it!!)