Quote Originally Posted by Cumulus View Post
Couldn't I also say ...тысячью рублями...? (in case we were talking about exactly 1000 rubles)
I would very strongly advise against it, even though I say things like that myself, occasionally.
I don't see, however, how it has anything to do with "exactness".

And, just to cover all bases, "с тысячей рублями в кармане" is just not possible.