Several people, including me, have bought these…
Neewer Black HDMI Input To VGA Adapter Converter For PC Laptop from Amazon and other places. I bought one to use in the school where I teach ICT 1/2 day per week and have only briefly tested it at home.
Unfortunately it has come to light in the forums that these adaptors can be harmful to your Raspberry Pi hardware (click here).
At least one person has reported that using one of these adaptors caused diode D1 to burn out. Subsequently it turns out that this Neewer device tries to draw 400 mA from the Pi and it has to pass through diode D1, which is only specced for 200mA.
I have tested the Neewer adaptor on my Pi, but only for a short time. I did have some issues with it the other day with Raspbian. It’s possible this was something to do with the extra power draw ?:-) It seems from comments on the forums that this device is not fully HDMI compliant and should probably not be used with the raspberry pi unless you hack it so it has its own power supply. You have been warned!