Recently the internet noticed the Raspberry Pi could drive LCD panels using DPI. This allows very inexpensive displays to be used with basically no additional hardware.
This is not a full post, just capturing some details from someone elses blog post so I don’t lose it (will my site become my next bookmark holder?).
http://blog.reasonablycorrect.com/raw-dpi-raspberry-pi/
Summary:
Total: $43.85
That being said, I see a Pi: 7" Display no Touchscreen 1024x600 w/ Mini Driver for $70 with no messing with HDMI.
I also recently purchased a 5" 800x480 screen with an hdmi driver off of a chinese vendor on ebay for $42.75. It just takes a month or so to arrive.