Por cuenta de

[AngelicaDeAlquezar]

As Rusty says, the examples can be generalized:
If you have "los tragos van por mi cuenta" and "los gastos serán por cuenta del inquilino", you can say "los tragos van/son/corren por cuenta de la casa".

[Tyrn]

Thanks!

So it is not idiomatic, like in English.

[AngelicaDeAlquezar]

Well, "por cuenta de" is invariable; it's only adapted to denote whose "property" is the "de" about.
The verbs don't change much either.

[Tyrn]

On the house, too.

—¿Te apetece tomar un batido?
—Bueno...
—Oh, la casa invita.

[AngelicaDeAlquezar]

The richness of languages is that there never is only one way to say things.