What is the ruling on purchasing a Saudi residency permit for the purpose of escaping widespread temptations and safeguarding one's religion and family, knowing that there is no way to obtain it without money?

If a person is forced to buy residency and finds no other way to obtain it, and doing so does not infringe upon anyone's rights, then there is no sin upon him. The sin falls upon the seller, unless the price is commensurate with the effort and money expended by the seller. Therefore, if you are in need of residency in the aforementioned country, there is no harm upon you in buying it if you cannot obtain it otherwise.