This is for the state of California.
I was in a car accident a couple of weeks ago. I only have liability insurance. After going through interviews by both insurance agents my insurance (Farmer’s Insurance) found me 100% not at fault. The other driver’s insurance (Mercury insurance) is only offering to pay 50% of damages. This is a big deal since I only have liability I would have to pay 50% from my pocket. I strongly believe I was not at fault (I was driving straight in my lane, a vehicle started making a left turn from a side street onto the street I was currently driving on. Before reaching the middle yellow lane isle where they could stop if need be, they stopped in my lane. I immediately braked and my front bumper hit the side of their front bumper.). There was also a witness that I flagged over, so there is a third party that would confirm my story. At this point should I get a lawyer? How can one say I’m 100% NOT at fault, while the other claim I’m 50% at fault?

If you have a witness then get a lawyer and fight it.
This is SO TYPICAL!!! Their insurance company is- of course- going to say 50%, because they don’t want to pay for it all!!!Did you do a police report? Was anyone ticketed? If no police report and no tickets-you might be stuck. If the other person was ticketed–you might check with an attorney. However–weigh out the cost of the attorney to the cost of fixing half your vehicle. If you must argue with them–do it with caution-as to not **** off the adjuster more (then they may not want to pay for as much-and don’t put that past them!!!) Stand your ground though!!
Mercury insurance? (china outfit?) Never heard of it. It was not your fault. The other partys insurance does not want to pay. (china outfit?) It figures, low class outfit. I’ll bet it’s one of those companies that insures the uninsurable. Tell them where to go. The other party failed to yield.
Did you get a accident report? An accident report would show which driver the officer considered the at fault party. In most states the at fault party is listed as driver #1 on the accident report. If you feel strongly that you are not at fault, by all means speak to an attorney. Take the attorney all correspondence between you and your insurance co.