Ants on a Log and a Cheating Winker - S7-E4
Other mistake: Sheldon (in the voice-over) says "it really brought what's his name and I closer together." The grammatically correct expression is "brought what's his name and ME closer together", and a stickler like Sheldon would not make that mistake.
Answer: It's as simple as money is tight, it's not "George's money", it's the family's money so the expenditure was selfish.
MovieFan612