After going around the interwebs. I've came across a few neat little inexpensive consoles. Some which i own myself. I believe by sharing these wonderful systems with you all. At least one of them can get the attention they deserve. This will be updated when and if I come across any new inexpensive consoles, handhelds, or computers under $100 USD.
The first i would like to share is the Bit Box. Which is a single microcontroller based console. More info can be found here: http://bitboxconsole.blogspot.com/
The UZEBOX, which is a small 8 bit build-it-yourself console. More info can be found at the official page here: http://belogic.com/uzebox/index.asp
Also the Hackvision, which is also a tiny simple arduino based system. More info can be found here: http://nootropicdesign.com/store/index.php?main_page=product_info&cPath=2&products_id=11
For the handheld game enthusiast. There is the Gamebuino, which is also a arduino based system. You can find more info here: http://gamebuino.com/shop/en/
There is also the upcoming Arduboy, which is also a arduino based system. You can find out more info on their official kickstarter page: https://www.kickstarter.com/projects/903888394/arduboy-card-sized-gaming/description
For the cheap opensource tiny computers. There is the Fignition, which is a very small and very simple build it yourself computer kit. Which uses the old school Forth programming language. For more info, checkout the link: https://sites.google.com/site/libby8dev/fignition
There is also the Micromite Companion. Which is also a tiny inexpensive computer/microcontroller. That uses the BASIC language. For more info on this computer, checkout the link: http://propellerpowered.com/shop/?page_id=1946