Due to change in plans, I went in a different direction and could not spend time on what Tim Shared.
As now I am back, will be exploring the method(s) mentioned there & implement, if serving my purpose.
Without involving PayPal, can I ensure user (registered user or yet to register user) buys (just presses a buy button) without making any payment ? The user has to especially show interest in those products.
If above solution is already there in Tim's link, I will spend good time on it in few days. If it's not, could you please share some ideas ?