Target has Medela parts on sale $3.44 for Membranes. 

Ear 1% cash back also Go To Ebates if you are new to Ebates you also get a $10 gift card for signing up it is totally free

I personally Love Ebates and they have paid me over to $800 for shopping only ;) (please use the ebates link above as that is my refer a fried link )

go to Ebates and search for Target new window will open as long as you check out in that window you will earn 1% cash back.