I just returned from 18 days in Myanmar — most of the time was with an Intrepid Travel group, so I don’t know the prices of accommodation (they took care of that). But here are some facts that might be helpful:
1. The official currency exchange (in modern offices with formal signage above the door) exchanged U.S. dollars for anywhere from 830 to 880 kyats (per $1). The rates for Singapore dollars and Euros were not bad at those offices. Because the U.S. dollars must be absolutely perfect (never used and never folded), it is easier to change Singapore dollars or Euros, because they do not show wear like the paper U.S. money. They reject many U.S. bills for very minor folds or marks.
2. There is an official currency exchange office in the Yangon airport near the baggage carousel. The rate was about 10 kyats less per dollar than the office at Bogyoke market (Scott market), on the same day (front side, at the east end). Given that 10 kyat is about 1 cents, this is not bad. And it’s convenient to get it done right away.
3. I used a free currency rate app on my iPhone (http://currencyapp.com/) that turned out to be very reliable for kyat rates. If you update it before you fly, you can check the rate in the airport against that and see if you’re willing to accept it.
4. Prices: You can easily eat something nice in a basic sit-down tea house or restaurant (I use the word loosely) for 1,000 to 3,000 kyats. A liter of bottled water costs 300 to 500 kyats most of the time. Fresh fruit juices are usually 1,000 kyats in safe (using bottled water) places. Small yellow mangoes were in season and cost 100 kyats each. Common souvenirs cost 1,000 to 5,000 each (little ones can be 10 for 2,000). I negotiated with a woodcarver for a beautiful 10-inch-high sitting Buddha image (not sandalwood, which costs more) and got a price of 28,000 kyats (his first price was 50,000). Longyi range from 2,000 to 7,000 (higher prices for nicer ones).
5. Single dollars and $5 bills: There are special prices for foreigners for entry to many things, such as some temples and the National Museum in Yangon. These prices are written in U.S. dollars. If you do not have U.S. dollars, they will always accept a one-to-one conversion, which is slightly bad for you (e.g. U.S. $1 = 1,000 kyats) because 1,000 kyats (today) is $1.13. So if you want to pinch pennies, be sure to have some clean, crisp U.S. $1 bills and two or three $5 bills. They are not so picky about these, but the bills still cannot be too worn. In shops where prices are marked in dollars, they will always accept kyats and usually (at least in my experience) the conversion rate in shops is fair. If not, argue with them.
6. If you must change money somewhere other than Yangon, the rates will certainly be unfavorable to you. But it (usually) can be done somewhere if you are desperate. Just be prepared to get a bad rate. Hotels (even good ones in Yangon) have poor rates, sometimes 100 kyat less than the market rate.
7. Make sure you get 5,000-kyat notes. That is the largest note available. Some money changers will try to give you 1,000-kyat notes — this will be 5x as much weight and bulk for you to carry! You will be able to get change in 1,000′s when you buy stuff. For example, 100 kyat notes (5,000) is about U.S. $570.
8. You can change kyats back in the Yangon airport just after going through immigration (international side) — there’s a bank office on the right side, “AGB” or something like that. The rate there on Monday was 860 or 870 kyats per U.S. dollar (sorry, I didn’t write it down). They also had some other currencies there.
9. There are black-market currency-exchange guys on every street corner in Yangon. They say politely, “Change money?” I asked two of them what their rates were, and they were lower than the official offices (780 and 790).
10. The official office at Bogyoke market (Scott market) has limited hours: 10 a.m. to noon, closed for lunch, then 1 p.m. to 2:30 p.m. They are closed on Mondays and all holidays.