Where to get small denominations of $U.S.
 

We are going to Cambodia in March. I keep reading that it is handy to have a reasonable quantity of $1& 5 U.S. notes for tips for service etc. We are going via Kuala Lumpa and Ho Chi Ming and then on to Phnom Penh & Siem Reap and wonder where we can obtain these smaller denominations . I also read that you normally pay in U.S but they give you change in Riel. Is this correct?

Almost all transactions in Cambodia are in US Dollars, Riel is used for fractional amounts of a dollar, since they don't us US coins, so you will often get dollars and Riel in change when paying for things. When you read that they give you change in Riel, it means that you get change for *A* dollar in Riel, not that all change is in Riel.

Small denominations of Dollars are useful, but you won't have much of a problem accumulating them on the go. I often arrive with nothing smaller than a $20 but have never had a problem getting change (although I've never asked a taxi driver to change a $100 - if I don't have small change before going out, I get it from the hotel).

Interesting to note that many ATM's, which are plentiful and dispense Dollars, will often give you a range of bills, rather than just the fewest notes to satisfy your withdrawal.

James looks like you will be coming from Oz. I wouldn't stress over getting too many small notes as Michael says you will accumulate easily. Try & have some 10's & 20's & then just use those to accumulate smaller stuff in the first days after you arrive. Have a great trip.
J

Do Cambodians take $100 bills readily? As we will pay our guide/driver in cash I'd like to keep the stack of paper notes as low as possible. Will the airport take a $50 bill to pay for
the visas? How about restaurants and shops taking the larger notes?

If your bill will be close to $100 then there's no problem using a $100 note. Just don't expect a taxi charging $5 to change a $100 (although he may surprise you). Immigration must take in a $1,000s dollar each flight, so they should have no problem changing a $100 bill. Larger restaurants and shops will have no problem with larger bills, but I always change a large bill at my hotel if I have no smaller ones on me when I'm going out.

and best to bring all new bills