What is the ruling on buying a car from someone for less than the market price, because they are in a hurry to travel and want to sell their belongings at a lower price due to their urgency?
Yes it is permissible; however, a Muslim shouldn't take advantage of other's difficult situations.
What`s the ruling on using the following materials in manufacturing cosmetics: olive oil, Vaseline, talc powder, glycerin, honey, almond oil, pine oil, galingale and marjoram?
All perfect praise be to Allah, The Lord of The Worlds, and may His peace and blessings be upon our Prophet Mohammad and upon all his family and companions. None of the above materials is forbidden, and it`s lawful to use them in manufacturing products that are beneficial to people. This is because, in principle, all things are lawful so long as there is no evidence in Sharia indicating otherwise. And Allah Knows Best.
What is the ruling on paying a sum of money to Saudi citizen in return of having Saudi residence? It is worth noting that this transation is labelled as a "worker's visa" but I am not going to work as such only to facilitate having it?
Allah The Almighty Says (What means): "O you who have believed, fear Allah and be with the truthful" [At-Tawbah/119]. False statements contradict truthfulness, and it is not permissible to write them. A Muslim has the right to live in any Islamic country, and those who prevent him will be accountable before Allah about their action and the justification for the prohibition. And Allah Knows Best.
Is it permissible to perform Tayammum for a month due to a medical condition that requires avoiding water?
Tayammum is permissible so long as the above excuse lasts. And Allah Knows Best.