If you have to ask, you can't afford it

Sales tactic supposedly used by those who cater to the filthy rich. The semi-humorous, ironic message is used to separate those who will (be able to) buy such items as yachts, million-dollar homes, small countries, gems, expensive art, and the like, from those who merely window-shop.

As with many useful phrases, it has been run into the ground by overuse.

"If you have to ask how much they cost, you obviously can't afford them, can you?"

(sigh). Honestly. That'd be the last time I ever shop at Oxfam.