I went to CVS last night and was in a rush to get on my way so I didn't check my receipt. I thought the bill was kind of high so when I sat to look at it when I got home I noticed that the Neutrogena makeup I bought did not ring up at Buy One Get One Free. I called CVS and they told me to just bring it back in along with my receipt and they will credit me for it.
This may not happen at all stores, but just make sure you check your receipt at the store, and don't wait until you get home like I did.
Btw, this sale is only a 3 day sale and ends Tuesday, Sept 8th. It is on ALL Neutrogena makeup items.