I love Athleta for all my business casual (and even more formal) needs! Free shipping/free returns makes it easy to try things on. I used to think I liked pants from Costco but after several purchases, they really just aren't as flattering and don't hold up as well so I quit spending money there.
I wear almost exclusively Athleta for all of my business travel meetings.
To get ideas:
https://athleta.gap.com/browse/categ...%20Work%20Shop
But I almost never buy anything full price - I shop from the sales page