I use Jim Stone's Split-Test Accelerator and can track what PPC campaigns lead to sales. This is done with a variable in the query string of the destination url. However, in order to track sales using this method, the user has to make a purchase in that session (and I have to transfer the query string via the url) otherwise I don't know what keywords lead to sales. I pretty much have to send Adwords visitors straight to the sales page if I'm to track what keywords lead to sales, which I don't want because it depends on a one off sale (I want to add them to my aweber account).
What software, script, or code can I use to track where visitors came from (mainly what keywords in a PPC campaign, but other sources would be amazing) who purchased my product?
The only idea I had was inserting the keyword they searched into a hidden field in aweber then appending those values to every url in the autoresponder (but then even that won't track properly unless some cookie exists because the query string would be lost). A scripted solution would make it a lot easier. Without such tracking, I'm wasting money on PPC.