For eyefinity it has to be active. If you're at 1920x1080 you only need a single link adapter (~$30) but for bigger resolution you need a dual link adapter which are usually $100 or more.
You might need to get a displayport to dvi adapter then use a dvi to vga adapter on top of that.
However, if you're only using 1 or 2 monitors you don't need an active adapter.
Thanks for the reply. I have found the following: Do you think that will work without going DP to DVI and then DVI to VGA
QVS DisplayPort Male to VGA Female Digital Video Adaptor
Supports both video mirroring and extended desktop modes / Supports Mini DisplayPort 1.1a input and DVI output / Up to 1080p
Connects any LCD/plasma HDTV or flat panel monitors with VGA Video port to Computers with DisplayPort. Its latching DP connector secure port connection. Supports both video mirroring and extended Desktop modes. DisplayPort 1.1a compliant and support screen Resolution up to WUXGA (1920x1200). It has Integrated triple 10-bit, 162 MHz video DAC for Analog VGA signal output.