I tried googling this but most answers that came up were regarding "cash" as bank deposits that a check is normally issued against. Not "cash-cash" or physical cash, as a bunch of bank notes.
Say one were to buy a $200K home or a $40K car in the U.S. but wished to pay in physical cash. Is it even legal past a certain amount? What kind of scrutiny can (s)he expect from regulatory agencies, IRS etc. if such a transaction surfaces up?
http://www.consumerismcommentary.com/buying-house-with-cash/
It looks like you can, but it's a bad idea because you lack protection of a receipt, there's no record of you actually giving the money over, and the money would need to be counted - bill by bill - which increases time and likelihood of error.
In general, paying large amounts in cash won't bring up any scrutiny because there's no record. How can the IRS scrutinize something that it can't know about? Of course, if you withdraw 200k from your bank account, or deposit 200k into it then the government would know and it would certainly be flagged as suspicious.
