I found that the apps I have stored in iTunes take up more than 10GB of space on my computer. Since I have a 128GB SSD I'd like to tell iTunes not to backup apps. I can download them again for free, anyway. If I uncheck the Sync Apps box, I get the message:
Are you sure you do not want to sync apps? All existing apps and their
data on the iPhone "kPhone" will be removed.
Best Answer
Back up apps is probably a wrong wording as you don't want to store the apps at all on your iTunes, if I understood you correct.
One option could be, to disable app sync. However, all apps are then probably deleted from your device and you have to download all of the again on your device again. If your apps will be deleted from your iOS device, you also will lose all the application data. Also the application data wont be backed up then to your iTunes (but could be backed up to iCloud).
Although you can redownload apps for free, you should keep in mind, that a developer (or Apple) can also remove an app from sale. It is then no longer possible to redownload the app. If you still have the app in your iTunes you still can continue to use it.