My 98 jeep wrangler has a knocking coming from the motor. I have had some people tell me I need a motor and some say it something simple. And ideas, sure can't afford a new motor.

Very first thing you need to do is verify the actual oil pressure using a mechanical gauge. Lowest pressure at idle, with a warmed up engine would be 20psi. I'd rather see it at 30.
If the pressure is good, then you could have a valve lifter or rocker arm that has worn. Those cause tapping noise, not knocking. Knocking is usually caused by a worn rod or main engine bearing. When either wear, oil pressure gets lower (why I said to check that) Knocking can also be caused by an undersized piston or a cracked flywheel (common on automatics). Piston noise generally only happens cold and is much less common than it use to be in Jeep engines.
So, everyone that gave you info on your problem may be right...The only way to know for sure would be to have someone that is experienced and honest check it out for you. How expensive the repair is will entirely depend upon what the actual diagnosis is.