Small place which I couldn't find on foody.vn but I was taken there by a local student. It was a good example of tasty phở for only 30,000d. I've been back a couple of times. It's a handy location for a cheap version. You can either have "phở gà" (chicken) or "phở bò" (beef).
Update: November 2018 - I think it's closed, sorry!