If you're anywhere near Cheshire Oaks (or similar discount retail park) then I can recommend the Elle macpherson lingerie shop. I bought two beautiful nursing bras from there this week, each reduced from £38 to £15 (everything in the shop was reduced to £15 max). I know £15 isn't as cheap as some, but they are lovely and comfy too, especially compared to the hideous cotton mono-boob bras I bought from M&S last time round.