Consignment stores, especially those in more affluent areas, are a good place for some decent clothes. Some items, never worn, or maybe tried on at home. It's like taking advantage of someone elses compulsive shopping habits.
Talking designer brand names, with quality fabric designed to last. When on a tight budget and in need of items, classic styles, with quality fabric will last a while, until you are in a better position to purchase newer clothes.

Just a piece or two, of what you need, to start. Couple pairs of pants/jeans, shirts. Look for styles that you can live with, and start seeing the new, healthier body.