Unless you are from a
GCC country you need a visa. Tourist visas are available for group tours.
Transit visas are easily available that allow you to pass through for no longer than 72 hours. You will need proof of a vehicle and/or airline tickets. They can be had for free or very cheaply.
Evidence of a visit to Israel may result in refusal of a visa/entry.
Saudi Arabia is the hub of Islamic religion and most of Muslims around the world assembles in Saudi Arabia for religion submit almost twice in a year and visas are free to all Muslims during the UMMRAH and Ramadan religion retreat.
To apply, email firstname.lastname@example.org