This post describes how I track E-junkie conversions resulting from my Google Ads campaigns sending users to my Wordpress site. This was very painful to figure out how to do (and I still may not have it all quite right). I'm posting it here in case others find it useful.
The "new" E-junkie thank you page automatically identifies your Google Analytics account and sends transaction data for the purchase to that account. While Analytics does track E-junkie transactions, it can't attribute most of those transactions (conversions) to the Google Ads campaign ads that brought the users to my web site.
After clicking my ads, most users don't purchase immediately. They often or usually purchase hours or days later after trying the free trial and/or visiting a tutorial Youtube video, and their later visit to purchase is classified by Analytics as a new session. So most of these transactions get a Source / Medium of (direct) / (none), not google / cpc. See this help article for a more detailed explanation:
https://support.google.com/analytics/answer/2679221?hl=en
Thus, I wanted to use Google Ads conversion tracking, which uses a different attribution model, allowing a conversion that happens days after an ad click to be properly attributed to the ad. Here are the steps I took; these may not be completely right, but they seem to work (I hope I didn't leave anything out):
I installed the free Google Site Kit on my Wordpress site and linked it with my Google Analytics and Tag Manager accounts.
In Google Ads, I created a conversion action:
https://support.google.com/google-ads/answer/6095821?hl=en&co=ADWORDS.IsAWNCustomer=true
In Google Tag Manager, I added a Conversion Linker tag and a Google Ads Conversion tag:
https://support.google.com/tagmanager/answer/6105160?hl=en
https://support.google.com/tagmanager/answer/7549390
In Google Analytics, I added e-junkie.com and fatfreecartpro.com to the Referral Exclusion List:
https://support.google.com/analytics/answer/2795830?hl=en
In E-junkie, I added the following snippets to the Product Thank-you Page HTML:
<script>
gtag('config', 'AW-528383436');
gtag('config', 'AW-528383436', {
'linker': {'accept_incoming': true}})
gtag('event', 'conversion', {
'send_to': 'AW-528383436/1DT7COeLyugBEMz7-fsB',
'value': [%gross%],
'currency': 'USD',
'transaction_id': '[%txn_id%]'});
</script>
The first gtag() provides my Google Ads account id.
The second gtag() sets up the Conversion Linker tag.
The third gtag() is the event snippet for the Google Ads conversion action, from Install The Tag Yourself. The 'value' has been changed from 1.0 to [%gross%], substituting in the total amount of the shopping cart. Similarly for 'transaction_id'.