If you do not use BIG Launcher and you only want to buy the full version of BIG Phone or BIG SMS, you can do it directly from the app you use.
Buy BIG Phone separately
To buy BIG Phone separately, open BIG Phone. The first item in the menu at the top is “Preferences”. Open it and choose “Buy / Refresh the full version”. A license screen will appear where you can purchase the full version of BIG Phone. Follow the instructions shown on the screen.
Buy BIG SMS separately
BIG SMS works in the same way. Open BIG SMS, choose “Preferences” from the top menu, then choose “Buy / Refresh the full version”. Continue with the purchase instructions shown by Google Play.
When you use BIG Launcher too
If you use BIG Launcher but do not want to buy the full version of BIG Launcher, and you only want BIG Phone or BIG SMS, open the app you want to buy and start the purchase from its own Preferences menu.