Andyw12345 now it wrote this as 'we sell pizza's'
This is sometimes called the
greengrocer's apostrophe, i.e. a redundant apostrophe before a plural inflection on notices promoting foodstuffs. (
Potatoe's is also quite common.)
Probably the establishment had found themselves with a surplus, after omitting apostrophes elsewhere (e.g. on the board advertising
Todays Specials).
MrP