3 Monitors with Macbook Pro Retina late 2014 13"

I currently have 3 27" Samsung monitors that have HDMI/VGA ports. When I use my macbook I like to close the lid and just use the external monitors. Unfortunately I can only output to two monitors at the same time.(Im not sure why.. but I've seen other people report similar issues) If I connect a 3rd monitor one of the first two monitors loses its display. (I can use 2 external monitors and the MacBooks screen if I want)

Currently I have 2 Mini DP adapters to HDMI convertors and one HDMI cable to connect to my monitors.

Reading other articles it was noted to support 3 monitors I would need to use a USB -> HDMI adapter, for instance the ones stargate sold, they are like 70-80 dollars. Would another option be to use the Thunderbolt to VGA adapter? Those are a lot less money.. but I hate buying adapters in case they do not work.

Or perhaps the Belkin Thunderbolt dock will allow this as well?