Okay I was never not single until I was 27 (save for a few 3–6 month stints here and there) and I have NEVER ever had a drink offered to me for free except by friends (and those are more like, “oh hey I’ll get this one”, with the expectation that I’ll also get a round another day, which I did/do)
But also I have a theory that could be because I rarely go to the bar with only other women. My major was engineering so the major of college friends were men. Whenever I hear stories of people getting offered drinks, they seem to women who are in groups of 1–2 other women. Small, non-coed bar buddies is maybe the difference?