I just picked up heaps of Ripe summer tops through Brands Exclusive for $25-$30 each but the sale has finished. It's worth while signing up for their daily emails though as they often have maternity clothes (including breast feeding tops) on sale.

Bump, Baby and Beyond have awesome mat/BF clothes too, a lot are 50% off retail prices. I've bought quite a bit from them too.

Mothercare usually have a 'sale' range online too