Sheldon: I was analyzing our lie and I believe we're in danger of Penny seeing through the ruse.
Leonard: How?
Sheldon: Simple: If she were to log on to SoCal physics group.org forward slash activities forward slash other, scroll down to seminars, download the PDF schedule, and look for the seminar on molecular positronium, well then, bippity boppity boo, our pants are metaphorically on fire!
Penny: Sheldon, have you any idea what time it is?
Sheldon Cooper: Of course I do. My watch is linked to the atomic clock in Boulder, Colorado. It's accurate to one-tenth of a second. But as I'm saying this, it occurs to me that you may have again been asking a rhetorical question.
Leonard: I already lied. Why cover it up with another lie?
Sheldon Cooper: Because your lie was painfully transparent, whereas my lie is exquisitely convoluted. While you were sleeping, I was busy weaving an un-unravelable web.
Suggested correction: Not being able to afford doesn't necessarily mean he doesn't have the money, especially a man like Sheldon. He works with a budget and he sticks to it. In his budget he has a certain amount set aside for rent, anything more than that and he can't afford it alone.
Nonsense. If he was sticking to a "rigid budget" he wouldn't have even thought of lending a hopeless credit risk like Penny a single cent. Instead he throws a huge bankroll at her without even discussing a repayment plan.
Rubbish, I stick to a strict budget but still have the money to lend to close friends. Like Penny is to him.
He might have different budgets for different things. People could get a higher margin because they could be of more use to the scientific mind of Sheldon.