One of my friend has developed web based products, which are accessible from Android, IPhone, Linux, Windows etc., and is offering them for low cost with source code.web based products offer with source codeweb based products offer with source code
Below is his purchase website link which displays more products. All are developed in B4X.https://b4xcode.onfastspring.com/
One may check them and contact him for more info. if required.
I am posting this message here on his behalf.