I know of the original Blue Grotto; but only went there once... What I remember is the New Blue Grotto, located on Melrose Ave & Heliotrope. Of course, Melrose is now Monroe and where the coffee house used to be is now a huge stadium.
I hung out there in the mid-sixties. You could get a decent cup of coffee for 25 cents and good nickle, dime and quarter bags of smoke ($5, $10, $25).
You could also find young women willing to entertain you for a modest fee; but watch your wallet...