hi, I am Sonal Bhavsar, I am a Tutor o'rhere. See there is a simple funda- Only Will = 100% Surity, that they will surely buy it. But who can show this much of surity? When the couple itself says that, we will buy it. But here we have a medium and that is BBC (which is not as sure as the couple itself) means will be buying = not so sure third party message give by BBC. Understood? I am confident that this funda will fix into your mind. Please, do give me feedback. Happy Learning!

For most English speakers, these variations would not be noticed. "I will be buying", "I will buy", "I am going to buy" would all be acceptable phrases. I think in the example given, the phrase "will be buying" indicates intent, while "will buy" indicates a fact. So, yes, they are expecting or planning or intending to buy that car, but the timing and the exact type of car is not yet determined so there is intent on their part but it is not a fact. There is so much flexibility in English that points like this can be very frustrating for the learner who wants to be accurate, yet the native speaker would likely not even notice the difference. I hope this helps.

Hello Brucedong, I think using the future continuous here " will be buying " instead of the future simple "will buy" indicates all of the previously mentioned : - uncertainty - intention - continuity

"Will be buying" may be a little off strict usage. "Will be..." is future continuous - something that will happen continually. "We will be taking a vacation." is valid, because it is something that would occur over time. "They will be buying a flash car and taking a vacation." can be used if both the act of buying a flash car and taking a vacation could be considered combined acts (resulting from their new-found money) would take place over time. In conclusion, there is almost no real information conveyed, compared with the sentence "They will buy a flash car and take a vacation." It's just that the future continuous form is used out of habit rather than justified usage. At least that's my opinion.