Some QR scanner apps on android devices can redirect the user to an add page and you have to be careful on the options selected.
For example if the user uses Gamma and selects the open option in the blue bar, it will take them to an advert.
For this particular QR scanner app, to get to the required page, the user has to select the URL again, not the open button.
We cannot dictate which QR app a user installs on their android device or whether they are protected from adds or redirects, though please be assured that no charge is requested by Spotlite to download the app.
If the user is unable to scan the QR code correctly from their invite link, we would suggest they open Google Play themselves and search for Spotlite to download.