I liked the vest top with drop cups from Emma Jane (I think it was) which I got from Figleaves. It was about £16 for cotton or £19 for bamboo (which is lovely and soft). What I liked was you could wear it under any top and it covered up your tummy and everything while you lifted your top e.g. t-shirt or blouse, so almost made any top a breast feeding top.
I got 2 in bamboo and still wear them to sleep in as so comfy, even though not Bfing any more LOL!
I think H&M are supposed to do quite affordable ones, but I could never get to a store with tiny baby as don't live in big city, so ended up buying second hand on ebay mostly...
Hope that helps?