Do you mind sharing your price range & specifically what you're looking for? Like, would you pay $20 for a top, $50, or $8? Do you need full on suits or just business-casual...black slacks w/ dressy yet work appropriate tops? Do you need shoes?
Here are my recs, in order, based on needing one-level below a full-out suit. Prices range $10-$50 per item (top, bottom, shoes, blazer/jacket) in the greater Seattle area.
1) Marshalls & Target (their Merona brand wedges are SO COMFORTABLE)
2) TJMaxx
3) Ross
4) Kohls
If you want to spend a little more $$ but not too much more, sign up for email coupons from The LOFT, Ann Taylor, Express, Banana Republic. Express & The Loft/Ann Taylor will be lower-priced and then Banana Republic is a little higher priced. I don't care how old you are - these places have quality, solid basics that can be had for usually 25-40% off if you sign up for sale coupons. Example = Express pants usually $70-$100 per pair. Coupons are often 25-35% or BOGO 1/2 off. Many women in their late 30s & beyond shun Express & The LOFT b/c they feel the stores target women in the 18-35 range - this is true. But they also sell VERY WELL FITTED BASICS. Black pants are black pants. They sell a few different cuts, rises, and lengths too.
Good luck w/ your shopping. FWIW - I don't wear other people's old clothes either. Gives me the heebie jeebies. Also, I have tried Kohls and shoped juniors, misses, and women's - I found all of their departments had ill-fitting clothes that were "cut" poorly. Same for JCPenny. A shame b/c JCPenny has The CUTEST clothes for Misses & Womens, I think! But they just don't fit well on me.
If JCPenny fits you though, they have VERY good prices & clothes that look like they came from Express, Loft, Ann Taylor.