Cellular service in Vietnam is nothing short of incredible. I can be in the remote country side with farmers and still get 3G service. The pricing compared to the American market is incredible too. I believe the total cost for my text, talk and data plan was close to 350,000 Vietnamese Dong or roughly $15 USD. This included ~100,000 Dong charge for the SIM card and the rest for the pay as you go plan. Incredibly the plan included 3GB worth of data.
My only trouble, how to get it to work on my android phone, the Samsung Galaxy S6. Hopefully this helps out others traveling to Vietnam.
After installing my SIM card, text and talk worked but I could not receive any data. After going to a couple different phone stores with no success, I finally figured out my problem through trial and error. Data networks require APN information similar to how you would connect to a wireless router. In my case I found a handy resource for Cellular APNs. I created an APN in the Mobile Data menu within Android settings. I had a plan from Viettel so the APN name is
v-internet with blank username and password. After saving the APN everything worked!