"Luna, you have to pay rent."
Princess Luna stopped what she was doing and turned to look at her sister with confuzzlement.
"Pardon me, sister?"
Celestia sighed. "You have to pay rent. You've been living at my castle which I built myself (with a little help) after you were banished for a year now and I've allowed it this long, but the time is nigh. You must pay rent."
Flabbergasted, Luna frowned. "B-but, w-what? Sister! This is preposterous. Making your own kin pay rent? What kind of lunatic does that?"
Celestia cocked an eyebrow. "Are you implying I'm as crazy as you, Luna?"
"No, sister."
Silence.
"Maybe," Luna quickly mumbled.
"Well, I believe you still owe me something."
Luna grumbled. "Seriously, Tia? You banished me in the moon for a millennium and yet you insist on some sort of payback for staying at your castle?"
"Of course. Do you think I let the maids and servants stay here of their own free will? I provide them a lodging and a paycheck, and they must in turn pay their rent as they serve me. They are free to leave my service anytime they wish. Or did you think that I was some sort of tyrant who would impose her will on a select group of ponies to do my bidding?"
Luna stumbled a little. "No! Why would you ever think I was implying that?"
"Because you still haven't answered my question about rent."
"Ugh," Luna moaned. "Fine! How many bits?"
Celestia's light smile quickly turned just a little sinister.
"Oh, you're not paying in bits."
Luna turned, a little confused, to look at Celestia, but did not like what she saw. Immediately, she knew what she was being asked of. Shaking her head, she pouted.
"No."
"Yes."
"No!"
"Get out of my castle."
"..."
"Well?"
"...fine..."
"What was that?"
Luna sneered at Celestia. "I said FINE!"
Celestia smiled. "That's a good girl."
"Shut up."
"You'll love what I have to offer on weekends."
"Don't rub it in."
"You know you secretly like them."
"QUIET, SISTER, OR I SHALL REMOVE MYSELF FROM THINE PRESENCE!"
"Oh, you're no fun."
"I'd still like to keep what remaining dignity I have left."