user575: Trading on Mt. Gox, which is now the largest Bitcoin exchange, started in July 2010 at an exchange rate of $0.05 USD. This comment suggests that on May 2010, bitcoins were traded at bitcoinmarket.com for roughly $0.004 USD.
What other exchanges existed this early in Bitcoin's life? What is the earliest/lowest recorded exchange rate?

user615: According to https://en.bitcoin.it/wiki/History:

2009
  October 5 Exchange rates published by New Liberty Standard. $1 = 1,309.03 BTC (and theymos thought NLS was overcharging[3])

It cites http://newlibertystandard.wetpaint.com/page/2009+Exchange+Rate
and
https://en.bitcoin.it/wiki/History#cite_note-2
That first citation seems to have a decent list of pre-May 2010 exchange rates.

575: <p>Trading on Mt. Gox, which is now the largest Bitcoin exchange, started in July 2010 at an exchange rate of $0.05 USD. <a href="https://bitcointalk.org/index.php?topic=137.msg1146#msg1146">This comment</a> suggests that on May 2010, bitcoins were traded at bitcoinmarket.com for roughly $0.004 USD.</p>

<p>What other exchanges existed this early in Bitcoin's life? What is the earliest/lowest recorded exchange rate?</p>
 615: <p>According to <a href="https://en.bitcoin.it/wiki/History" rel="nofollow">https://en.bitcoin.it/wiki/History</a>:</p>

<blockquote>
  <p>2009
  October 5 Exchange rates published by New Liberty Standard. $1 = 1,309.03 BTC (and theymos thought NLS was overcharging[3])</p>
</blockquote>

<p>It cites <a href="http://newlibertystandard.wetpaint.com/page/2009+Exchange+Rate" rel="nofollow">http://newlibertystandard.wetpaint.com/page/2009+Exchange+Rate</a>
and
<a href="https://en.bitcoin.it/wiki/History#cite_note-2" rel="nofollow">https://en.bitcoin.it/wiki/History#cite_note-2</a></p>

<p>That first citation seems to have a decent list of pre-May 2010 exchange rates.</p>
