Paying to paint the fish

Something that you could could afford to do, but won't do because you think it's a waste of money. Going above and beyond what's necessary for a normal person, and paying a premium price for it.

John - "Did you hear that Will put in a koi pond and had the fish painted color coordinated to his decor?"
Bob - "That's the most literal example of "paying to paint the fish" I've ever heard."