On specially marked packs of Stayfree branded pads, there is a a Try Me Free promotion. Purchase the product and send in for a full refund of the price you brought it for.
The packs have a yellow circle sticker on it. I can't find a website for this but I saw the promotion on supermarket shelves. Stickers are tagged on most stayfree product ranges and the product can cost up to $8.
Limit one per household and must send in barcode.
I bought this with the intention of claiming the cashback - then I lost the receipt!