I think that a better idea for a Test Pilot experiment would be to auto complete an online shopping cart up to a budget chosen by the user (e.g. the amount that gets you free shipping on certain websites, but you decide it) and then the Test Pilot experiment could track prices and suggest “legal” carts that are the closest to the budget, from above. The Test Pilot experiment should take the suggestions directly from what items the user asked to track, and show how much is needed in order to reach one’s fixed budget.
I think this is feasible with a little bit of organization. Maybe even possible to make it as a “cart feature” in Price Wise, if it doesn’t deviate too much.