When was the first price quote?

[xeverse]

What's the earliest price data point available?

[kjj]

I believe it was when Sirius sold 5000 BTC for $5.

I've seen recent references to it (example), but I haven't bothered looking for a primary source or the date.

This thread may be amusing in today's context.

[Melbustus]

What's the earliest price data point available?

There's the following: "October 5, 2009:    Exchange rates published by New Liberty Standard. $1 = 1,309.03 BTC (and theymos thought NLS was overcharging[3])"
From: https://en.bitcoin.it/wiki/History