Spanish to English Other Idioms / Maxims / Sayings

Context: en España cualquier coste parecía pequeño; daba igual comprar un buen ático, que contratar unas buenas vacaciones, que hacer un buen palacio de exposiciones; es lo que tiene la pólvora del rey, que la paga el rey.

I was actually planning to leave it like this: in Spain, any cost seemed small. We saw no difference between buying nice penthouses, booking nice vacations, or building a fancy convention center. It makes no difference what you spend when someone else is paying for it.

I understand the history of where the term came from in Spain, but I was wondering what people think is the best idiomatic equivalent in English. I can't think of anything besides, "being on your boss's expense account."

Thank you,
Marie