Merchant with most caps in Fallout 3

I'm trying to sell all of the plasma rifles I got from doing Broken Steel, but they sell for over 1600 caps, and I can't find any traders that have that many.

So who are the richest merchants to go to? or do I just need buy ammo and stimpaks to make up the difference?

Solution 1:

If you invest in the caravans via the Merchant Empire quest, the caravans are by far the richest - they will stock between 500 and 1200 caps each (roughly). Most other merchants top out at less than 500, although Moira Brown can apparently go as high as 3,000. (The Wikia mentions this but gives no details).

That said, as you (and commenters) have noted, trading for caps is generally a losing proposition - trade for other stuff instead, and use caps to make up the difference. Zero-weight items work best, so that you don't become encumbered. Bonus points if they're actually useful.