After using the Sima Quickonnect for all of my sub-$10 quick release needs, another product has shown up on the horizon recently. A clone of the Manfrotto 323 RC2 quick release system, this Chinese knock-off is a solid product that comes in at 1/4 of the price of the original. Both systems are great for allowing you to move your camera between DIY builds, but this Manfrotto clone is the better buy in my opinion.
The New Jersey eBay supplier seems to randomly jack up the price up to $108.48 (why?), so double check before you buy, or use the Hong Kong supplier.
Manfrotto Clone, Hong Kong Supplier ($9.30)
Sima Quickonnect, Amazon ($8-12)