“Fightback eBons” is a analytics platform, that allows you to have a summary of all your shoppings.
Every bon has a random unique identifier. You receive a normal paper bon at the checkout. At home you can type in the identifier in the web application. The web application receives all the information written on the paper as digital data.
Data from paying customers are not sold. A company can not track your shopping behavior if you pay in cash. Non paying customers will get personalized offers for discounts that a company offers, paying customers can if they want to.
Payback and bonus cards are a worst case scenario of tracking beside online shopping. Building an open source application would help to give back the control of the data to the customers.
Big companies will no cooperate. A workaround is to scan the bons your self and apply text processing. This process is a lot of work to implement, has many points of failure and is expensive for calculation / in external processing.
Maybe https://bon-online.de is a software which is quite similar to this idea.