You heard right (more or less), and you're assumption is right. "I'd like... uh... a beer". "Etto" (sometimes with the E longer than other times) also works similarly and is more formal... if you can believe that.
It can also be used to get someone's attention, by simply stating either rather blankly. Tone and other words appended can change this from harmless to angry.
Another usage is just to buy time. Translation wise it would probably the same, but also colloquially could sound more like, "Let's see..." like you might say while looking over a menu while your server anxiously awaits you to decide.
Basic usage will sound different since the variable in the sentence (drinks in this case) are located in a different part of the sentence. For example if you're asked what you want, a valid reply might be.
In short... both are pretty flexible.