Right now, the cheapest "new" video card sold directly by Newegg is a $35 NVidia 210 which was new in 2010. Interestingly, reviews from that time period suggest that it sold for $30 after rebate. It has HDMI, DVI and VGA ports.
In the $50 range you can get an R7 350, which promises 4K support (although I suspect that will be at 30Hz) and would certainly be enough to light a monitor with enough oomph to put shadows and transparency effects on your windows.
In the $50 range you can get an R7 350, which promises 4K support (although I suspect that will be at 30Hz) and would certainly be enough to light a monitor with enough oomph to put shadows and transparency effects on your windows.