Did not have a clue what the price on this comic was all about. I was used to seeing all of the UK pence variants but had never seen this weird symbol before, so thought it was an error of some kind. Posted it on another forum here and someone gave me the poop on it. That symbol stands for one shilling which was equal to twelve pence. Copy with regular price right below it.
I have a bunch of variants, error issues, and signed FF comics scanned front and back on my website: https://dekventures.com/FantasticFour/fantastic-four-v-1-variants-signed-reprints/