Definately op shops are the way to go. Loooove the op shops
Another thing, although this might not work for you, I have t shirts and trackies that I pretty much live in daily, which is ok for me as I am a SAHM of a small child, it wouldnt be suitable if you were working in an office or anything though..... but I find that they see me through, and they still fit after losing some weight, so i dont need to keep replacing them (until I am at my goal weight of course, then its shopping spree!
) I also have a basic wardrobe (picked up from op shops) that see's me through any situation out of the home... I have 1 pair black dress pants, 1 nice shirt, 1 pair jeans, 1 dressy but casual top, 1 black skirt, 1 jacket. I think that is about the basics you might need (tell me if i forgot anything).... but so far it has seen me through xx