Recommendations for an Inexpensive and Weatherproof Computer?

I'm looking for a relatively inexpensive (<$150 USD) computer that can run Linux, has an Ethernet port, can connect to peripherals via USB, and can be connected to a display via HDMI. It needs to be as weatherproof as a good outdoor WLAN router (i.e. can withstand copious precipitation and extremes of temperature). Any recommendations?