Waifu Tax

It is the financial expenditures one must undertake in order to prove one's love and admiration for a particular waifu. Such expenditures may consist of sexy body pillows, figures of your Waifu in a bikini, posters of your waifu in a bikini, etc.

Otaku 1: I spent 600 dollars to get a Rias Gremory body pillow, wedding dress figure, and exclusive charachter poster.

Otaku 2: I understand my brother... that's quite the waifu tax you paid.