There was a recent discussion where someone talked about comics going from cheap, disposable entertainment to heavily appealing to collectors. Variant covers and first appearances were mentioned. I'm wondering when publishers started directly courting collectors, rather than when people started collecting. One thing that prompted this question was someone posting a cover of New Teen Titans #1. I don't pay much attention to covers, so despite having read it, this was when I first really noticed the "1st Collector's Item Issue" printed on the cover. So, just how old is the trend of overtly aiming at collectors?
EDIT: If anyone with the ability to edit titles wants to correct my typo, feel free to do so.