Many vendors come through the hẻm (lane) everyday shouting out what they have to sell. This brush vendor is typical.
Recently, there has been a dramatic increase in the number of music CD vendors. They come through with a loudspeaker blaring whatever is inserted in the CD player at the moment. They power the player with a battery.
They always draw a crowd of neighbors looking to get the latest Vietnamese tunes. The CDs cost 5,000 Vietnamese đồng a CD (US$.31). At this price, you know the recording label and artist are not getting any royalties.
You can try out a CD in the player to see if you want to buy it. We bought one CD, but it did not work in my Mac laptop -- the CD volume could not be mounted and the computer spit the CD back out. You get what you pay for.