In automations where a contact converts once they make a purchase, you may want to use a goal to move that contact to a different part of the automation.
To create a goal that activates when a contact makes a purchase, use the condition "Last Order Date is Current date."
Our first instinct might be to use the condition "Has made a purchase." However, this condition applies to any contact who has ever made a purchase — including contacts who have yet to enter the automation — and will result in contacts entering and immediately jumping to the goal.
Consider that "Last Order Date is Current date" will also apply to any contact who made a purchase that day before triggering the automation. If this is a problem, consider adding more conditions to narrow the possibilities (like Product ID or Has made a purchase in a particular store) or creating a separate automation that adds a tag when a contact makes a purchase and uses that tag in place of Ecommerce conditions.