Both ladies' beer and ladies beer are acceptable, but there is a slightly different implication depending on which you use. Ladies' beer is written in the possessive form, and thus implies รขโ‚ฌยฆ Ladies and gentlemen everyone [nothing] friends / folks / team avoid mixing and matching:

And s'up, honoured guests? Are kind of weird. Not impossible รขโ‚ฌยฆ Hence, there is no ambiguity with the men, and for the same reason no ambiguity with the ladies. Ladies is the plural form of lady, so the apostrophe goes to the right - ladies'. If you are wondering why we รขโ‚ฌยฆ

Ladies is the plural form of lady, so the apostrophe goes to the right - ladies'. If you are wondering why we รขโ‚ฌยฆ