Transportation: Airport to City Center
I highly recommend taking Bus 109. It's only 1 USD and will take you to the city center (District 1). The attendants were helpful and spoke English. If you're uncertain of which stop to get off at they'll be able to assist you.
https://www.itourvn.com/blog/how-to-take-shuttle-buses-from-tan-son-nhat-international-airport-to-saigon-ho-chi-minh-city-center
Once you're in the city center there are several of options to choose from. The best way to get around (in my opinion) is by back of the bike. It may look intimidating but I felt safe and it's affordable. There are also"man" powered bikes with carriage options, which I felt like such a tourist and a horrible person for doing so, but it's actually a way for the locals to get around as well. Do be sure to stand firm with the price. I kept being haggled while I was eating breakfast, so I finally agreed to this guy to bike me around for a low cost of 25,000 VND, which is less than 2 USD. I verified with the guy 3 times that the price he offered was correct and he agreed. Then when I had arrived at my destination he tried to get more money out of me. 30 USD to be exact, so be sure to stand your ground.
Accommodation:
Hotels are very affordable in Ho Chi Minh. This trip I chose to stay at a hostel near Bui Vein Walking Street. It was only 7 USD a night and very accessible to sites I wanted to check out. The only down fall is that the night scene on Bui Vein went until 0200, so if you plan on getting a good nights rest I recommend bringing some ear plugs.
Things to do/See:
If you have more than 2 days to spare and want to visit Northern Vietnam it's very affordable to fly with Viet Jet. If you book early enough you can fly for 35 USD. Otherwise, last minute it's about 100 USD. https://www.vietjetair.com/Sites/Web/en-US/Home
Back of the Bike Tours-(Cost 77 USD) This was my favorite activity on this trip. Definitely do the food tour. https://backofthebiketours.com/
War Remnants Museum-(Cost 40,000 VND/1.72 USD)
Reunification Palace
Ben Thanh Market
Saigon Central Post Office
Notre Dame Cathedral of Saigon
Food:
I highly suggest making a stop to see The Lunch Lady. She was made famous by Anthony Bourdain and she offers a different dish each day. As a tourist, her team will place several food items on the table, which you will be charged for (just roll with it). With all items included my meal was still less than 6 USD.
While in Vietnam, here are some must have food items that should not be passed up.
Pho-I ate everyday. Even for breakfast.
Bun (vermicelli noodle bowl)
Spring Rolls
Banh Mi
Papaya Salad
Vietnamese Coffee