Per the posting guidelines this can’t be a deal so I’m putting it in the forums instead.
My dentist gave me a box of this to try instead of doubling-up on regular paracetamol + ibuprofen as it’s supposed to work faster. I visited the web site to read more about it and saw the banner ad to get your purchase price refunded (up to $10) if you buy it from any store and you’re not happy with results after 7 days.
Basically, they’re shouting you a free box.
Edit: Per the comments below it would appear some people don't like being advised of something they may not be aware of already so I guess those folks like to stumble across it themselves. Also, I'm not advocating you should rort the offer just to get a freebie, I encourage you to genuinely give the product a try and make an informed decision as to whether you're satisfied with it or not.
People have mixed opinions on whether it should be deal
Eg
https://www.ozbargain.com.au/node/53194
https://www.ozbargain.com.au/node/79462