M.M.
I believe you're talking about Lillypadz. I have yet to use them (didn't need them the first time around), but my SIL used them with 2 kids and LOVED them.
They're not expensive, actually. About $20/pair, and one pair should last you through about 6 months.
They stick to your breasts with adhesive and suppress the nipple, which prevents leakage. When you're ready to take the off, you just wash with soap and water.