Pham Ngu Lao is known as the backpacker's area in HCM. The street is lined with affordable hotels and hostels as well as cafes and restaurants. You can buy food at local shops for a $1-2, and coffee is a lot cheaper. Pham Ngu Lao is also lively at night as some places are 24 hours and some close up real late. A Bahn mi from a local seller would cost a dollar, fruit shakes go at around $1.50. The streets are very safe even at night. Bars are lively and the beer here is cheap!