In caps.. I have about 80K, give or take a few thousand. But I also don't trade in my NCR, Legion and pre-war money, so I have a buttload of those too. All told I'd guess I have 90-100K. This is mostly through jury-rigging expensive weapons and looking in every single container I come across.
EDIT: http://steamcommunity.com/profiles/76561198053081900/screenshot/541798319031132018 is how much I had right after 'Dead Money'.
Speaking of pre-war money and it's value, does anyone else find it odd that 1 stack of pre-war money is worth more than 1 Legion Denarius?
A singe Legion Denarius is made out of silver, while a stack of pre-war money is useless paper!
Well, silver and gold are only valuable because we make it valuable. They're not particularly useful in a post-apocalyptic wasteland. Maybe if the NCR has heavy industry back home...?