Ho Chi Minh City's Tan Son Nhat International Airport ( SGN) is the usual destination for those coming to the south of Vietnam.
NOTE: Please do not post comments about taxis here, use the more popular HCMC Forum instead.

When you arrive at the Immigration desks, all that is usually required from you is your passport (with visa inside - if required) and your incoming flight number. See the article about VOA if you have to collect your visa at the airport. That's it. If you have anything to declare to Customs, when you go downstairs you should declare them and fill out a separate form.

Leaving the International terminal building, the ATM area is at the right hand end. The official currency in Vietnam is the Dong (vnd), in March 2016 trades at approximately 22,250 to USD. You will find 4 / 6 working ATM's, some with a maximum withdrawal of 4,000,000 Dong. Do not leave the terminal without 300,000/500,000 Dong, it is the only legal currency in Vietnam and you will need it for paying food and taxi. The currency exchange shops inside the terminal are ok, with some currency better than some banks. See the link at the bottom of the page for more information.

Taxis are located on the left part of the terminal, the cost to most hotels in District 1 is from 150,000 to 170,000 dong. Do not use USD as it is an opportunity to get ripped off. Please use only the two most reliable taxi company, Mai Linh, with car and van white and green, and the white Vinasun more frequent in HCMC. Depending on the hours taxi may be waiting at the curb, ignore any name apart the two mentioned, when one arrive the manager will magically appears and will ask for destination giving you a slip of paper with the taxi number.

You can also pay in advance at the Taxi counter before going out of the airport but it will not be cheaper.  Make sure you get a metered taxi!! The rates are regulated, and are based on distance and time waiting while en route. Read the cost on the meter to make sure you are not getting ripped off. The airport exit toll fee is 10,000 dong and the driver must pay it but they will always add 10/15.000 dong at your arrival. People (touts) with fake Vinasun badge may try and grab you and direct you to their taxi, and give you a rate of 250.000/500.000 dong. Don't do it, get a metered cab instead.

The cheapest way is to take public city Bus # 152 parking in a lane few steps away on the right side from the Arrival's entrance.
It takes you downtown to the Bus Station on the opposite side of the traffic round about from Ben Thanh market, at a cost of 5000 dong per person and per piece of big luggage. It runs every 20 minutes from 6 am until 6 pm.

Or you can chose the new modern bus to City Center/ Pham Ngu Lao area, Bus 109 in yellow just operate from March 2016. It run through the main street of city center and final stop at Pham Ngu Lao street. They run every 15-20 minutes between 5:30 am and 1:30 am, cost for one-way trip is 20,000 dong and the entire journey takes approximately 45 minutes. 

If you need somewhere to store your bags for whatever reason, turn to the right as you exit the International terminal and head to the end of the building. You will find a staffed luggage storage area. You can leave your baggage there for as long as you need, cost is around 23.000 dong per hour. 

Times have changed a little. Rates have come down quite abit (including touts) because of UBER! Use UBER and you will pay around 80-90,000 dong. However, the same fake taxi touts will come to you and claim that they were the UBER you called. So be vigilant and look out for the correct number plate. Shouldn't be too difficult to match 1 to 1 ;) 

Taking a taxi to the airport should cost the same as leaving it, so please follow the tips on the previous section. The airport fee is not paid arriving at the airport (only leaving) so if the driver will ask for it just mention you have already paid it when arrived.
Before entering the departure/check in area, at the departure hall, there are numerous cafes and fast food outlets around. Dominos and Burger King are there outside the terminal, so during the day you have to eat under the sun. WiFi password is always the same, printed on any receipt. If chicken is your thing, there is a Popeye's downstairs. Be sure to ask the staff for the WIFI Password. These fast food restaurants have a good menu selection and normal prices in Vietnamese Dong. This area is your last chance to purchase a bottled mineral water at a decent price; read 20.000 vnd. (Look for StarCafe) Remember that the bottle will not pass the security check.

The airport departure tax is now included in the price of your ticket. After check-in, the first thing you hit is Customs with Immigration following. The security check follows. Make sure you don't have any sharps, excess liquids etc with you as they will be confiscated.

After the security check, There are two cafes to the left and right of the security check. Near Gate 14, and Gate 20. They have limited seatings, so it is best you head to the Food Court Upstairs (Level3) At the Food Court, this would be the place to get your last fix of vietnamese Pho noodles there. Free WIFI is available courtesy of Illy Cafe. The Illy Cappuccino, the best Vietnam has to offer,  is 4usd, same price with the Starbucks in the City Center, Illy serves Pizzas too. If you would like to chill or relax, there is a Sports Bar near Illy Cafe with comfortable seats and with WIFI. Food is decent in the Bar. Burger King is also up there. 

Tan Son Nhat airport is fairly small and although there are duty frees on sale the range is limited. If you want to buy any local specialities, buy before you go to the airport since you have more choices in the city center. Know the limits (especially liquids) applying to both checked in and carry on items. Even more so if transiting another country. Be aware that certain countries prohibit the import of certain goods, foods etc. Check before you buy. No point buying only to have it confiscated on arrival at your destination. If you buy DVD there is the possibility that they x-ray the luggage and ask for a fine, so it is better to forget about them. 

If you find your flight is delayed or you need to store your bags for whatever reason, head for the arrivals level of the International terminal. There are lifts, stairs and escalators at the end of the building. Over to the left you will find a staffed luggage storage area. You can leave your baggage there for as long as you need, cost is around 23.000 dong per hour. 

If you have a long wait nearby the airport, there is the Parkson store (with its food hall) opposite both terminals which is passed on the way into the airport (about a 10-15 minute walk) along with CGV Cinemas. Do drop by if you have ample time to spare.