It was either random Super Friends merchandise (like coloring books or lunch boxes), back issues of Batman Family or Brave and Bold, or the lovely Yvonne Craig in syndication on TV. I have fuzzy memories of what my first exposure to Batgirl really was. There is something so spectacular about the bright purple and yellow Batgirl from the classic 1960's Batman show.
Batman Classic TV Series - Yvonne Craig Batgirl Mini-Bust - Diamond Select 2016