You can, no doubt, negotiate your claim with an insurance company yourself in order to avoid the cost of hiring a personal injury lawyer. But, the insurance companies and their lawyer are very well aware of the fact that you do not know the legal statements about your legal rights and remedies. They, therefore, try to do everything they can to take advantage of you and to effect the lowest possible settlement.
In case you decide to sue, they might even attempt to elicit statements from you that will damage your position.
On the other hand, a personal injury lawyer can help you obtain a favorable settlement. The amount that you will get as compensation for the damage done will certainly exceed the attorney fee.
Personal injury lawyers, generally, accept personal injury cases on the basis of what is known as the "contingency fee". Contingent fee implies that if they win your case, a percentage of the award received should be given to them as their fee. On the other hand, if they lose, no attorney fee is given to them.
Most civil litigation settles short of trial. Therefore, you can get the issue of cost clarified by your lawyer. But, do bear in mind that the attorney fee is different from costs associated with your case. That is, filing fee for your lawsuit is not deducted from the attorney fee. Generally, the attorney contingent fee varies from state to state. However, in most of the states, the contingency fee is between one third and 40% of the compensation received as a personal injury award.
Besides, in case of workers' compensation, attorney fee is tightly regulated and is lower than what is charged for regular personal injury matters.
You can always try to negotiate a reduction of the attorney's contingent fee.