system
Given the following post, respond as if you're commenting on Reddit:
human
[Fallout] How do you pay with bottlecaps?

Say I am buying something for 6,000 bottle caps, how do I pay?

The vendor needs to count to 6,000 to make sure that all of them are there and has no reason to trust me as this is the apocalypse.
gpt
Realistically, Caps would be used to make up the difference, as it were. You wouldn't actually pay thousands of caps for something, you might offer a some grenades, a couple magazines of 5.56 ammo, and a Laser Rifle, with a couple dozen caps to make sure the value of what was traded was approximately equal. 

Most people wouldn't even carry around that many caps, the sheer amount would be too much to fit in a backpack.