Consider a kid's-eye view of the world. Food appears on the table. A car and driver chauffeur you from place to place. Flick a switch and the computer turns on. Flick another and you're watching Nickelodeon.
Life is good.
Life is cheap. With so much taken care of for them, it's not surprising that children can't appreciate what it costs to keep a household running. It's little wonder that they can't understand why a new bike just doesn't fit into the family budget. And, remember, you're on your own now, so you'll have to rent an apartment. Sorry, but you're in the hole already.