The Netgear PVT3000 Miracast / WiDi device is on sale for $39 in Amazon's "Deal of the Day" As the name suggests, the price is today only.

Amazon.com : NETGEAR Push2TV Wireless Display HDMI Adapter with Miracast (PTV3000) Certified for use with Kindle Fire HDX : Streaming Media Clients : Electronics

It seems to be the cheapest, tested-working Miracast device for the T100.

According to price tracking site CamelCamelCamel.com, this is the cheapest it's been. It typically hovers around $60, the same as the other quality Miracast devices.

NETGEAR Push2TV Wireless Display HDMI Adapter with Miracast (PTV3000) Certified for use with Kindle Fire HDX | Amazon price tracker / tracking, Amazon price history charts, Amazon price watches, Amazon price drop alerts | camelcamelcamel.com

Here's the thread discussing setup of the T100 with this device.
http://www.transformerforums.com/for...tml#post303251