Unfortunately, with the sheer amount of users and check-ins that have been generated in just the first week of Supermarket Check-In, the adverts are a necessary evil to help pay for the cloud hosting charges.
I've been asked many times if it would be possibly to have a remove adverts button and I am looking at integrating this as part of a "Pro" in-app purchase just as soon as I have finished more important additions to the functionality and stability of the app.
In addition to removing adverts, this Pro upgrade will allow you to set your favourite Retailers/Stores so they appear first, decide whether stores disappear from the list if they have not had a Check-In within a certain time period, and manually set a location so you can view details outside of your local area.
In the meantime, if you would like to help get through the long days (and nights) that I'm working on enhancing Supermarket Check-In, you can "Buy Me A (Virtual!) Coffee" using the link below:
As long as you signup to the app with the same email address that you use to Buy Me A Coffee, once the remove adverts functionality is up an running I'll make sure the Pro upgrade is applied to your account.