Before you accept any job in Saudi Arabia, the fundamental thing is to read the contract very carefully. You must be absolutely clear who your sponsor is. Remember, one cannot work or even enter Saudi Arabia without a sponsor. A sponsor has to necessarily be a Saudi citizen who should have taken prior permission from his government to bring an expatriate for work inside the kingdom. The sponsor could be either an individual or a company. Knowing the background of your sponsor could save you from a lot of trouble, but if you do not have this information, you have to dig in a bit deeper.
Be absolutely sure that you would be working only for your sponsor. There are also cases of people coming in under a person's sponsorship by paying him a certain sum of money and then once inside the kingdom working for someone else. This is called "free-visa" in expat jargon, (i.e., once inside KSA you are "free" to work wherever you like) and if you are planning to do this, you are really asking for trouble. Please desist from any such moves.
Read and re-read your contract several times. This is the only document which is going to protect you. Now answer this simple questionnaire:
1. Are you going to pay for your air tickets to go to the kingdom?
2. Are you going to pay for your exit / reentry visa and iqama charges?
3. Are you going to bear all your medical expenses in the kingdom?
4. Is it clearly mentioned in your contract about your vacation (once a year, once in two years, etc.)
5. Is your local agent in your home country reputable? (Watch this blog for further information, if you are not so sure)
6. Has your compensation been clearly mentioned giving all the break-up (Basic, transportation, housing, education for the kids, medical, dental, paid vacation, etc.)
If your answer to any of the above questions is "No", then my friend, you better step back. Remember, your contract decides your future in the kingdom, so do not leave any scope for ambiguity. Get everything in WRITING, this is very important. DO NOT GO BY VERBAL ASSURANCES.