system
Given the following post, respond as if you're commenting on Reddit:
human
[MCU/Iron Man 3] How did Stark pay at the hardware store?

He's believed to be dead (and he's obviously trying not to be recognized, with the hoodie and sunglasses), so his credit cards probably wouldn't work. And considering he had to leave in a hurry from what was left of his house on Malibu Point, he likely didn't think to grab any cash, and he seems like he's not the kind of person to carry much with him; he probably uses credit everywhere. So how did he purchase all that stuff to build things before he went to the Mandarin's mansion?

EDIT: And how did he get a hotel room?
gpt
In addition to his personal credit cards, Tony probably also has some business credit cards for Stark Industries that would still work fine.

It's possible that he also carries some other forms of payment for when he doesn't want to be recognized or tracked.