Try wrap dresses. They tend to last longer in terms of fit as you get smaller (or bigger)!
Definitely check the clearance racks!
JC Penney's Worthington brand is nice and reasonably priced. I've found a style of slacks I really like there and just bought a size down, which I'll continue to do as I need new clothes. Takes the frustration out of shopping since I know exactly what I like.
Good luck! You'll feel so much better once you spend a little money and update your wardrobe no matter what you end up getting, as long as it fits.