How to agree on an exchange rate over PM?

[sethsethseth]

There is a lag time during the pm exchange where the rates fluctuate.  Is there some site that lists the mtgox price at x time, so you could agree to sell at trading price a few minutes from now?

[BitcoinMint.US]

If you're that concerned, you have a couple of options that come to mind.

1) You could use a service like bit-pay.com to generate a payment button that is set at a fixed USD price.  They would take 1%, and you would have to wait until they made payment to you, so the risk is still there.  This is a good solution if you are selling items over a long period of time, like on a website.

2) You could open an account at bitcoinica.com and 'short' the amount of bitcoins that you're asking for in the trade.  You would most incur a small loss with this strategy due to the 'spread' on bitcoinica.  This is a good strategy if you're dealing with extremely large bitcoin trades.  Not advised for the newbie.

3) You could give the person you're trading with a deadline to make payment.  You'll have to wait for confirmations to your account no matter what you do, which will open you up to a little risk.  This is the most common and least risky way for small trades on the forum.

[sethsethseth]

I should clarify.  This is for trading between 2 people who trust each other, but when one of us pm's the other and says "hey do you want to buy at x rate, this is what it says on mtgox", then the other guy gets the PM like an hour later and checks the mtgox price, which will have changed, giving him an advantage.  It would be better to say "let's complete this trade at whatever the exchange rate is 4 hours from now at 10pm, reply by then to confirm."  I just need to know where I can see timestamped mtgox trades.

[tcatm]

Try http://bitcoincharts.com/charts/mtgoxUSD and click "Load raw data" (below the chart). It'll show you a table with the same data (+weighted price for each interval) as is shown in the chart.