Promotion Group Usage without Assets ?

Hi Experts,

I Just started the reading of Promotion group concepts. Can some explain my queries.

1) Can some explain the business case where i can use the  Promotion group for New Quote ( No Assets for Customer, Fresh new quote) .... Is there any business case  ?

2) To use the promotion group concepts do i need at least one Asset ?

I have one business case , can some one explain how can use this promotion group concept for this case.

1) customer orders the TV, Internet, Telephony ( all are root products) in quote (Still no assets) . So i want to propose  the Device at Reduced Price..