It’s really easy to “steal” a short book by finding a corner in the store and then reading the whole thing before anyone notices. It’s a little bit harder with longer books. And I really don’t recommend trying to memorize an entire dictionary in stealth mode.
More seriously, notice that the word for money, “okane” has an honorific “o” at the beginning. Like I mentioned back in strip 53 there are certain words that almost always have a polite honorific attached to them and “okane” is one of them.
買う = かう = to buy
ゲーム = game
お金 = おかね = money
Yellow: こにちは！ What are you doing here at the mall?
Blue: What about you?
Blue: Why would you come to the mall with no money?
Yellow: I played the game for three hours on the store’s demo system before they asked me to leave.