Q132: How can I or my customers receive sms notifications before the rental?

Your account comes with 5 free SMSes that you can use to test this feature. Then you will need to purchase SMS packs in the subscription tab.

To have the system send SMSes to you, you'll need to specify your mobile number in your account settings (click on your user name on top of any page while logged in). Then, you'll need to go to the notifications page (available in the settings tab or from the 'quick links' menu) and specify which events should trigger sending of SMSes.